Pharm II Exam 4

A 60-year-old immigrant from Latin America was told she had hypertension and should be taking antihypertensive medication. She decides to take an herbal medication from an online "holistic pharmacy." One week after starting the medication, she is found unconscious in her apartment. In the emergency department, her blood pressure is 50/0 mm Hg and heart rate is 40 bpm. Respirations are 20/min; pupils are slightly constricted. Bowel sounds are present. Which of the following would be the most effective cardiovascular stimulant? (A) Amphetamine (B) Clonidine (C) Isoproterenol (D) Norepinephrine (E) Tyramine

"Herbal" medications often contain potent synthetic drugs in addition to (or instead of) the advertised constituents. This patient shows signs of sympathetic autonomic failure: hypotension, inappropriate bradycardia, constricted pupils. These signs are compatible with a large overdose of a drug that causes marked depletion of stored catecholamine transmitter such as reserpine, an obsolete but inexpensive antihypertensive agent. The indirect-acting agents (amphetamines and tyramine) act through catecholamines in (or released from) the nerve terminal and would therefore be ineffective in this patient. Clonidine acts primarily on presynaptic nerve endings although it can activate α2 receptors located elsewhere. Isoproterenol would stimulate the heart but has no α-agonist action and might exacerbate the hypotension. Norepinephrine has the necessary combination of direct action and a spectrum that includes α1, α2, and β1 effects. The answer is D.

Head and neck irradiation in cancer patients can decrease salivary secretion and cause dry mouth. All of the following drugs or classes of drugs are theoretically useful in improving secretion of saliva in these patients except: A. Muscarinic antagonists. B. Muscarinic agonists. C. Anticholinesterase agents. D. Pilocarpine. E. Neostigmine.

A. Muscarinic antagonists.

A patient with heart failure and significantly reduced cardiac output requires surgical anesthesia. Which of the following would you expect to see in this patient? A. Slower induction time with IV anesthetics. B. Need for increased dosage of IV anesthetics. C. Slower induction time with inhaled anesthetics. D. Enhanced removal of inhaled anesthetics to peripheral tissues

A. Slower induction time with IV anesthetics.

Which of the following statements about fentanyl is correct? A. Fentanyl is 100 times more potent than morphine. B. Its withdrawal symptoms can be relieved by naloxone. C. The active metabolites of fentanyl can cause seizures. D. It is most effective by oral administration.

A. Fentanyl is 100 times more potent than morphine.

Which one of the following is a potent intravenous anesthetic but a weak analgesic? A. Propofol. B. Benzodiazepines. C. Ketamine. D. Fentanyl. E. Isoflurane.

A. Propofol.

Which of the following is a systemic effect of a muscarinic agonist? A. Reduced heart rate (bradycardia). B. Increased blood pressure. C. Mydriasis (dilation of the pupil). D. Reduced urinary frequency. E. Constipation.

A. Reduced heart rate (bradycardia).

Which of the following agents is available as a patch for once-daily use and is likely to provide steady drug levels to treat Alzheimer's disease? A. Rivastigmine. B. Donepezil. C. Memantine. D. Galantamine. E. Glatiramer

A. Rivastigmine.

An elderly female who lives in a farm house was brought to the emergency room in serious condition after ingesting a liquid from an unlabeled bottle found near her bed, apparently in a suicide attempt. She presented with diarrhea, frequent urination, convulsions, breathing difficulties, constricted pupils (miosis), and excessive salivation. Which of the following is correct regarding this patient? A. She most likely consumed an organophosphate pesticide. B. The symptoms are consistent with sympathetic activation. C. Her symptoms can be treated using an anticholinesterase agent. D. Her symptoms can be treated using a cholinergic agonist.

A. She most likely consumed an organophosphate pesticide

Botulinum toxin blocks the release of acetylcholine from cholinergic nerve terminals. Which of the following is a possible effect of botulinum toxin? A. Skeletal muscle paralysis. B. Improvement of myasthenia gravis symptoms. C. Increased salivation. D. Reduced heart rate.

A. Skeletal muscle paralysis.

Which statement about the toxicity of local anesthetics is correct? (A) Bupivacaine is the safest local anesthetic to use in patients at risk for cardiac arrhythmias. (B) In overdosage, hyperventilation (with oxygen) is helpful to correct acidosis and lower extracellular potassium (C) Intravenous injection of local anesthetics may stimulate ectopic cardiac pacemaker activity (D) Most local anesthetics cause vasoconstriction (E) Serious cardiovascular reactions are more likely to occur with tetracaine than with bupivacaine

Acidosis resulting from tissue hypoxia favors local anesthetic toxicity because these drugs bind more avidly (or dissociate more slowly) from the sodium channel binding site when they are in the charged state. (Note that onset of therapeutic effect may be slower because charged local anesthetics penetrate the membrane less rapidly; see text.) Hyperkalemia depolarizes the membrane, which also favors local anesthetic binding. Oxygenation reduces both acidosis and hyperkalemia. Bupivacaine may cause severe cardiotoxicity including arrhythmias. The answer is B.

Clinical studies have shown that adrenoceptor blockers have many useful effects in patients. However, a number of drug toxicities have been documented. Adverse effects that limit the use of adrenoceptor blockers include which one of the following? (A) Bronchoconstriction from α-blocking agents (B) Acute heart failure exacerbation from β blockers (C) Impaired blood sugar response with α blockers (D) Increased intraocular pressure with β blockers (E) Sleep disturbances from α-blocking drugs

Although chronic heart failure is often treated with certain β blockers, acute heart failure can be precipitated by these drugs. Choices A, C, and E reverse the correct pairing of receptor subtype (α versus β) with effect. Choice D reverses the direction of change of intraocular pressure. The answer is B.

A 7-year-old boy with a previous history of bee sting allergy is brought to the emergency department after being stung by 3 bees. Which of the following are probable signs of the anaphylactic reaction to bee stings? (A) Bronchodilation, tachycardia, hypertension, vomiting, diarrhea (B) Bronchospasm, tachycardia, hypotension, laryngeal edema (C) Diarrhea, bradycardia, vomiting (D) Laryngeal edema, bradycardia, hypotension, diarrhea (E) Miosis, tachycardia, vomiting, diarrhea

Anaphylaxis is caused by the release of several mediators. Leukotrienes and certain proteins are the most important of these. They cause bronchospasm and laryngeal edema and marked vasodilation with severe hypotension. Tachycardia is a common reflex response to the hypotension. Gastrointestinal disturbance is not as common nor as dangerous. The answer is B.

Which statement concerning nitrous oxide is accurate? (A) A useful component of anesthesia protocols because it lacks cardiovascular depression (B) Anemia is a common adverse effect in patients exposed to nitrous oxide for periods longer than 2 h (C) It is the most potent of the inhaled anesthetics (D) There is a direct association between the use of nitrous oxide and malignant hyperthermia (E) Up to 50% of nitrous oxide is eliminated via hepatic metabolism

Anemia has not been reported in patients exposed to nitrous oxide anesthesia for periods as long as 6 h. Nitrous oxide is the least potent of the inhaled anesthetics, and the compound has not been implicated in malignant hyperthermia. More than 98% of the gas is eliminated via exhalation. The answer is A.

A 65-year-old woman with impaired renal function and a necrotic ulcer in the sole of her right foot is admitted to the ward from the emergency department. She has long-standing type 2 diabetes mellitus and you wish to examine her retinas for possible vascular changes. Which of the following drugs is a good choice when pupillary dilation—but not cycloplegia—is desired? (A) Isoproterenol (B) Norepinephrine (C) Phenylephrine (D) Pilocarpine (E) Tropicamide

Antimuscarinics (tropicamide) are mydriatic and cycloplegic; α-sympathomimetic agonists are only mydriatic in the eye. Isoproterenol has negligible effects on the eye. Norepinephrine penetrates the conjunctiva poorly and would produce intense vasoconstriction. Pilocarpine causes miosis. Phenylephrine is well-absorbed from the conjunctival sac and produces useful mydriasis for 10-30 minutes. The answer is C.

Ms Brown has been treated for myasthenia gravis for several years. She reports to the emergency department complaining of recent onset of weakness of her hands, diplopia, and difficulty swallowing. She may be suffering from a change in response to her myasthenia therapy, that is, a cholinergic or a myasthenic crisis. Which of the following is the best drug for distinguishing between myasthenic crisis (insufficient therapy) and cholinergic crisis (excessive therapy)? (A) Atropine (B) Edrophonium (C) Physostigmine (D) Pralidoxime (E) Pyridostigmine

Any of the cholinesterase inhibitors (choices B, C, or E) would effectively correct myasthenic crisis. However, because cholinergic crisis (if that is what is causing the symptoms) would be worsened by a cholinomimetic, we choose the shortest-acting cholinesterase inhibitor, edrophonium. The answer is B.

Among NSAIDs, aspirin is unique because it (A) Irreversibly inhibits its target enzyme (B) Prevents episodes of gouty arthritis with long-term use (C) Reduces fever (D) Reduces the risk of colon cancer (E) Selectively inhibits the COX-2 enzyme

Aspirin differs from other NSAIDs by irreversibly inhibiting cyclooxygenase. The answer is A.

A 52-year-old woman presented with intense pain, warmth, and redness in the first toe on her left foot. Examination of fluid withdrawn from the inflamed joint revealed crystals of uric acid In the treatment of this woman's acute attack of gout, a high dose of colchicine will reduce the pain and inflammation. However, many physicians prefer to treat acute gout with a corticosteroid or indomethacin because high doses of colchicine are likely to cause (A) Behavioral changes that include psychosis (B) High blood pressure (C) Rash (D) Severe diarrhea (E) Sudden gastrointestinal bleeding

At doses needed to treat acute gout, colchicine frequently causes significant diarrhea. Such gastrointestinal effects are less likely with the lower doses used in chronic gout. The answer is D.

Which one of the following can be blocked by atropine? (A) Decreased blood pressure caused by hexamethonium (B) Increased blood pressure caused by nicotine (C) Increased skeletal muscle strength caused by neostigmine (D) Tachycardia caused by exercise (E) Sweating caused by exercise

Atropine blocks muscarinic receptors and inhibits parasympathomimetic effects. Nicotine can induce both parasympathomimetic and sympathomimetic effects by virtue of its ganglion-stimulating action. Hypertension and exercise-induced tachycardia reflect sympathetic discharge with norepinephrine release and therefore would not be blocked by atropine. Exercise-induced sweating is another sympathomimetic response, but it is mediated by acetylcholine released from sympathetic nerve fibers at eccrine sweat glands. The answer is E.

Which of the following antiparkinsonian drugs may cause vasospasm? A. Amantadine. B. Bromocriptine. C. Carbidopa. D. Entacapone. E. Ropinirole

B. Bromocriptine.

Modest improvement in the memory of patients with Alzheimer's disease may occur with drugs that increase transmission at which of the following receptors? A. Adrenergic. B. Cholinergic. C. Dopaminergic. D. GABAergic. E. Serotonergic

B. Cholinergic.

Which of the following is correct regarding the neuromuscular blockers (NMBs)? A. Nondepolarizing NMBs are administered orally. B. Cholinesterase inhibitors reduce the effects of nondepolarizing NMBs. C. Nondepolarizing NMBs affect diaphragm muscles first. D. Effects of depolarizing neuromuscular blockers can be reversed using cholinesterase inhibitors.

B. Cholinesterase inhibitors reduce the effects of nondepolarizing NMBs.

A young woman is brought into the emergency room. She is unconscious, and she has pupillary constriction and depressed respiration. Based on reports, an opioid overdose is almost certain. Which of the listed opioids will exhibit a full and immediate response to treatment with naloxone? A. Meperidine. B. Morphine. C. Buprenorphine. D. Fentanyl.

B. Morphine.

If an ophthalmologist wants to dilate the pupils for an eye examination, which of the following drugs/classes of drugs could be theoretically useful? A. Muscarinic receptor activator (agonist). B. Muscarinic receptor inhibitor (antagonist). C. Acetylcholine. D. Pilocarpine. E. Neostigmine.

B. Muscarinic receptor inhibitor (antagonist).

A 30-year-old woman undergoes abdominal surgery. In spite of minimal tissue damage, complete ileus (absence of bowel motility) follows, and she complains of severe bloating. She also finds it difficult to urinate. Mild cholinomimetic stimulation with bethanechol or neostigmine is often effective in relieving these complications of surgery. Neostigmine and bethanechol in moderate doses have significantly different effects on which one of the following? (A) Gastric secretory cells (B) Vascular endothelium (C) Salivary glands (D) Sweat glands (E) Ureteral tone

Because neostigmine acts on the enzyme cholinesterase, which is present at all cholinergic synapses, this drug increases acetylcholine effects at nicotinic junctions as well as muscarinic ones. Bethanechol, on the other hand, is a direct-acting agent that is selective for muscarinic receptors regardless of whether the receptors are innervated or not. The muscarinic receptors on vascular endothelial cells are not innervated and respond only to direct-acting drugs. The answer is B.

Which one of the following drugs causes vasodilation that can be blocked by atropine? (A) Benztropine (B) Bethanechol (C) Botulinum toxin (D) Cyclopentolate (E) Edrophonium (F) Neostigmine (G) Pralidoxime

Bethanechol (Chapter 7) causes vasodilation by directly activating muscarinic receptors on the endothelium of blood vessels. This effect can be blocked by atropine. Indirectly acting agents (AChE inhibitors) do not typically cause vasodilation because the endothelial receptors are not innervated and acetylcholine is not released at this site. Pralidoxime is a distracter in this answer list. The answer is B.

Peripheral adverse effects of levodopa, including nausea, hypotension, and cardiac arrhythmias, can be diminished by including which of the following drugs in the therapy? A. Amantadine. B. Ropinirole. C. Carbidopa. D. Tolcapone. E. Pramipexole.

C. Carbidopa.

A 52-year-old woman will be undergoing sedation with propofol for a brief diagnostic procedure. Which of the following is an advantage of propofol for this patient? A. Rapid analgesia. B. Sustained duration. C. Decreased incidence of nausea and vomiting. D. Less pain at the injection site.

C. Decreased incidence of nausea and vomiting.

A 57-year-old male has been treated with oxycodone for chronic nonmalignant pain for over 2 years. He is now reporting increased pain in the afternoon while at work. Which of the following opioids is a short-acting opioid and is the best choice for this patient's breakthrough pain? A. Methadone. B. Pentazocine. C. Hydrocodone. D. Nalbuphine

C. Hydrocodone.

A 76-year-old female with renal insufficiency presents to the clinic with severe pain secondary to a compression fracture in the lumbar spine. She reports that the pain has been uncontrolled with tramadol, and it is decided to start treatment with an opioid. Which of the following is the best opioid for this patient? A. Meperidine. B. Fentanyl transdermal patch. C. Hydrocodone. D. Morphine.

C. Hydrocodone.

In Alzheimer's disease, there is a deficiency of cholinergic neuronal function in the brain. Theoretically, which of the following strategies will be useful in treating the symptoms of Alzheimer's disease? A. Inhibiting cholinergic receptors in the brain. B. Inhibiting the release of acetylcholine in the brain. C. Inhibiting the acetylcholinesterase enzyme in the brain. D. Activating the acetylcholinesterase enzyme in the brain.

C. Inhibiting the acetylcholinesterase enzyme in the brain.

The potency of inhaled anesthetics is defined quantitatively as: A. Blood/gas partition coefficient. B. Cerebrovascular resistance. C. Minimum alveolar concentration. D. Diffusion hypoxia.

C. Minimum alveolar concentration.

During an ophthalmic surgical procedure, the surgeon wanted to constrict the pupil of the patient using a miotic drug. However, he accidentally used another drug that caused dilation of the pupil (mydriasis) instead. Most likely, which of the following drugs did he use? A. Acetylcholine. B. Pilocarpine. C. Tropicamide. D. Phentolamine. E. Bethanechol.

C. Tropicamide.

An 80-year-old patient with asthma and low blood pressure requires anesthesia for an emergency surgical procedure. Which of the following agents would be most appropriate for inducing anesthesia in this patient? A. Desflurane. B. Ketamine. C. Propofol. D. Thiopental.

C. Propofol.

Which of the following agents may cause tremors as a side effect and, thus, should be used with caution in patients with Parkinson's disease, even though it is also indicated for the treatment of dementia associated with Parkinson's disease? A. Benztropine. B. Rotigotine. C. Rivastigmine. D. Dimethyl fumarate.

C. Rivastigmine.

32-year-old woman requests an epidural to ease labor pains. She reports that she had an allergic reaction to Novocain (procaine) at the dentist's office. Which of the following local anesthetics would be appropriate for use in an epidural for this patient? A. Chloroprocaine. B. Mepivacaine. C. Ropivacaine. D. Tetracaine.

C. Ropivacaine.

Which of the following statements regarding methadone is correct? A. Methadone is an excellent choice for analgesia in most patients since there are limited drug-drug interactions. B. The equianalgesic potency of methadone is similar to that of morphine. C. The duration of analgesia for methadone is much shorter than the elimination half-life. D. The active metabolites of methadone accumulate in patients with renal dysfunction.

C. The duration of analgesia for methadone is much shorter than the elimination half-life.

Which of the following is correct regarding local anesthetics? A. They affect only small, unmyelinated nerve fibers. B. They have either a lipophilic or a hydrophilic group. C. They have either an amide or an ester linkage. D. They are unaffected by pH of the tissue and pKa of the drug. E. In their ionized form, they interact with the protein receptor of calcium channels.

C. They have either an amide or an ester linkage.

Parasympathetic nerve stimulation and a slow infusion of bethanechol will each (A) Cause ganglion cell depolarization (B) Cause skeletal muscle end plate depolarization (C) Cause vasodilation (D) Increase bladder tone (E) Increase heart rate

Choice (E) is not correct because the vagus slows the heart. Parasympathetic nerve stimulation does not cause vasodilation (most vessels do not receive parasympathetic innervation), so choice (C) is incorrect. Ganglion cells and the end plate contain nicotinic receptors, which are not affected by bethanechol, a direct-acting muscarinic agonist. The answer is D.

Mr Green has just been diagnosed with dysautonomia (chronic idiopathic autonomic insufficiency). You are considering different therapies for his disease. Pyridostigmine and neostigmine may cause which one of the following in this patient? (A) Bronchodilation (B) Cycloplegia (C) Diarrhea (D) Irreversible inhibition of acetylcholinesterase (E) Reduced gastric acid secretion

Cholinesterase inhibition is typically associated with increased (never decreased) bowel activity. (Fortunately, many patients become tolerant to this effect.) The answer is C.

Which of the following is the primary second-messenger process in the contraction of the ciliary muscle when focusing on near objects? (A) cAMP (cyclic adenosine monophosphate) (B) DAG (diacylglycerol) (C) Depolarizing influx of sodium ions via a channel (D) IP3 (inositol 1,4,5-trisphosphate) (E) NO (nitric oxide)

Cholinomimetics cause smooth muscle contraction mainly through the release of intracellular calcium. This release is triggered by an increase in IP3 acting on receptors in the endoplasmic reticulum. The answer is D.

An emergency department patient with severe pain thought to be of gastrointestinal origin received 80 mg of meperidine. He subsequently developed a severe reaction characterized by tachycardia, hypertension, hyperpyrexia, and seizures. Questioning revealed that the patient had been taking a drug for a psychiatric condition. Which drug is most likely to be responsible for this untoward interaction with meperidine? (A) Alprazolam (B) Bupropion (C) Lithium (D) Phenelzine (E) Mirtazapine

Concomitant administration of meperidine and monoamine oxidase inhibitors such as isocarboxazid or phenelzine has resulted in life-threatening hyperpyrexic reactions that may culminate in seizures or coma. Such reactions have occurred even when the MAO inhibitor was administered more than a week after a patient had been treated with meperidine. Note that concomitant use of selective serotonin reuptake inhibitors and meperidine has resulted in the serotonin syndrome, another life-threatening drug interaction (see Chapter 16). The answer is D.

Nondepolarizing neuromuscular blockers are associated with all of the following except: A. Initial activation of ACh receptor and depolarization of the motor end plate. B. Effects are reversed by acetylcholinesterase inhibitors. C. Intermediate to long duration of action. D. Bind but do not activate ACh receptor. E. Most of these agents have minimal cardiovascular effects.

Correct answer = A. Activation of the ACh receptor is attributed to depolarizing agents (succinylcholine). B, C, and D are true for nondepolarizing agents. Pancuronium may cause tachycardia and hypertension; rocuronium and vecuronium have favorable cardiovascular safety profiles

Which one of the following drugs, when administered intravenously, can decrease blood flow to the skin, increase blood flow to skeletal muscle, and increase the force and rate of cardiac contraction? A. Epinephrine. B. Isoproterenol. C. Norepinephrine. D. Phenylephrine. E. Terbutaline.

Correct answer = A. Exogenous epinephrine stimulates α and β receptors equally well, leading to the constriction of blood vessels in tissues such as skin and dilation of other blood vessels in tissues such as skeletal muscle. Epinephrine also has positive chronotropic and inotropic effects in the heart. Exogenous norepinephrine constricts blood vessels only and causes a reflex bradycardia because of its strong α-adrenergic-stimulating properties. Phenylephrine has similar effects. Isoproterenol stimulates β receptors and would not cause vasoconstriction of cutaneous vessels.

Which one of the following is a potent intravenous anesthetic but a weak analgesic? A. Propofol. B. Benzodiazepines. C. Ketamine. D. Etomidate. E. Isoflurane.

Correct answer = A. Propofol is a potent anesthetic but a weak analgesic. It is the most widely used intravenously administered general anesthetic. It has a high lipid solubility. The other choices do not fit this profile.

Modest improvement in the memory of patients with Alzheimer's disease may occur with drugs that increase transmission at which of the following receptors? A. Adrenergic. B. Cholinergic. C. Dopaminergic. D. GABAergic. E. Serotonergic.

Correct answer = B. Acetylcholinesterase inhibitors, such as rivastigmine, increase cholinergic transmission in the CNS and may cause a modest delay in the progression of Alzheimer's disease. Increased transmission at the other types of receptors listed does not result in improved memory.

Which of the following antiparkinson drugs may cause peripheral vasospasm? A. Amantadine. B. Bromocriptine. C. Carbidopa. D. Entacapone. E. Ropinirole.

Correct answer = B. Bromocriptine is a dopaminereceptor agonist that may cause vasospasm. It is contraindicated in patients with peripheral vascular disease. Ropinirole directly stimulates dopamine receptors, but it does not cause vasospasm. The other drugs do not act directly on dopamine receptors.

A 68-year-old man presents to the emergency department with acute heart failure. The patient requires immediate drug therapy to improve his cardiac function. Which one of the following drugs would be most beneficial? A. Albuterol. B. Dobutamine. C. Epinephrine. D. Norepinephrine. E. Phenylephrine.

Correct answer = B. Dobutamine increases cardiac output without significantly increasing heart rate, a complicating condition in heart failure. Because epinephrine can significantly increase heart rate, it is not typically used for acute heart failure. Both norepinephrine and phenylephrine have significant α1-receptor-stimulating properties. The subsequent increase in blood pressure would worsen the heart failure. Albuterol, a β2-selective-receptor agonist, would not significantly improve contractility of the heart

A patient on a diagnostic test for myasthenia gravis would be expected to have improved neuromuscular function after being treated with: A. Donepezil. B. Edrophonium. C. Atropine. D. Echothiophate. E. Neostigmine.

Correct answer = B. Edrophonium is a short-acting inhibitor of acetylcholinesterase (AChE) that is used to diagnose myasthenia gravis. It is a quaternary compound and does not enter the central nervous system. Donepezil, isoflurophate, and neostigmine are also AChEs but with longer actions. Donepezil is used in the treatment of Alzheimer disease. Echothiophate has some activity in treating open-angle glaucoma. Neostigmine is used in the treatment of myasthenia gravis but is not used in its diagnosis. Atropine is a cholinergic antagonist and, thus, would have the opposite effects.

A young man is brought into the emergency room. He is unconscious, and he has pupillary constriction and depressed respiration. You note needle marks on his legs. You administer naltrexone, and he awakens. This agent was effective because: A. The patient was suffering from an overdose of a benzodiazepine. B. Naltrexone antagonizes opiates at the receptor site. C. Naltrexone is a stimulant of the central nervous system. D. Naltrexone binds to the opioid and inactivates it. E. The patient was suffering from an overdose of meperidine.

Correct answer = B. The indications are that the patient is suffering from an overdose of an opioid such as heroin. Naltrexone antagonizes the opioid by displacing it from the receptor. It is used in preference to naloxone, because it is longer acting and, thus, can act as long as the opiate is in the body. Meperidine causes the pupils to dilate.

Which of the following may precipitate an attack of open-angle glaucoma if instilled into the eye? A. Physostigmine. B. Atropine. C. Pilocarpine. D. Echothiophate. E. Tropicamide.

Correct answer = B. The mydriatic effect of atropine can result in the narrowing of the canal of Schlemm leading to an increase in intraocular pressure. Physostigmine, pilocarpine, and echothiophate would cause miosis. Tropicamide produces mydriasis without increasing intraocular pressure because of its shorter duration of action.

The prolonged apnea sometimes seen in patients who have undergone an operation in which succinylcholine was used as a muscle relaxant has been shown to be due to: A. Urinary atony. B. Depressed levels of plasma cholinesterase. C. A mutation in acetylcholinesterase. D. A mutation in the nicotinic receptor at the neuromuscular junction. E. Weak histamine-releasing action.

Correct answer = B. These patients have a genetic deficiency of the nonspecific plasma cholinesterase that is required for the termination of succinylcholine's action. The other choices would not produce apnea.

Which one of the following combinations of antiparkinson drugs is an appropriate therapy? A. Amantadine, carbidopa, and entacapone. B. Levodopa, carbidopa, and entacapone. C. Pramipexole, carbidopa, and entacapone. D. Ropinirole, selegiline, and entacapone. E. Ropinirole, carbidopa, and selegiline.

Correct answer = B. To reduce the dose of levodopa and its peripheral side effects, the peripheral decarboxylase inhibitor, carbidopa, is coadministered. As a result of this combination, more levodopa is available for metabolism by catechol-O-methyltransferase (COMT) to 3-methyldopa, which competes with dopa for the active transport processes into the central nervous system. By administering entacapone (an inhibitor of COMT), the competing product is not formed, and more dopa enters the brain. The other choices are not appropriate, because neither peripheral decarboxylase nor COMT nor monoamine oxidase metabolizes amantadine or the direct-acting dopamine agonists, ropinirole and pramipexole.

In which one of the following conditions would aspirin be contraindicated? A. Myalgia. B. Fever. C. Peptic ulcer. D. Rheumatoid arthritis. E. Unstable angina.

Correct answer = C. Among the nonsteroidal anti-inflammatory drugs, aspirin is one of the worst for causing gastric irritation. Aspirin is an effective analgesic and is used to reduce muscle pain. It also has antipyretic actions, so it can be used to treat fever. Because of its anti-inflammatory properties, aspirin is used to treat pain related to the inflammatory process (for example, in the treatment of rheumatoid arthritis). Low doses of aspirin also decrease the incidence of transient ischemic attacks.

Peripheral adverse effects of levodopa, including nausea, hypotension, and cardiac arrhythmias, can be diminished by including which of the following drugs in the therapy? A. Amantadine. B. Bromocriptine. C. Carbidopa. D. Entacapone. E. Ropinirole.

Correct answer = C. Carbidopa inhibits the peripheral decarboxylation of levodopa to dopamine, thereby diminishing the gastrointestinal and cardiovascular side effects of levodopa. The other agents listed do not ameliorate levodopa's adverse effects.

The pain of a patient with bone cancer has been managed with a morphine pump. However, he has become tolerant to morphine. Which of the following might be indicated to ameliorate his pain? A. Meperidine. B. Codeine. C. Fentanyl. D. Methadone. E. Buprenorphine.

Correct answer = C. Fentanyl is used in anesthesia. It produces analgesia and is usually injected epidurally. However, its analgesic action is also beneficial in cancer patients. It is available as a transdermal patch and an oral transmucosal preparation. Meperidine and codeine show cross-tolerance with morphine and, thus, would not be effective. Buprenorphine, like methadone, is used in opiate detoxification and could precipitate withdrawal.

A heroin addict has entered a rehabilitation program that requires that she take methadone. Methadone is effective in this situation because it: A. Is an antagonist at the morphine receptors. B. Is a non-narcotic. C. Is longer acting than heroin, conferring milder withdrawal than with the latter drug. D. Does not cause constipation. E. Is nonaddictive.

Correct answer = C. Methadone is used in rehabilitation programs as a substitute for heroin. It has similar euphorigenic and analgesic activity, is orally active, and can be easily controlled. Most important, it is long acting, and the withdrawal the patient undergoes as she is being weaned off the drug is much milder than would be the case with heroin. Methadone is a synthetic, orally effective opioid that acts at the μ receptors. It does cause constipation and can be addictive.

A soldier's unit has come under attack with a nerve agent. The symptoms exhibited are skeletal muscle paralysis, profuse bronchial secretions, miosis, bradycardia, and convulsions. The alarm indicates exposure to an organophosphate. What is the correct treatment? A. Do nothing until you can confirm the nature of the nerve agent. B. Administer atropine, and attempt to confirm the nature of the nerve agent. C. Administer atropine and 2-PAM (pralidoxime). D. Administer pralidoxime.

Correct answer = C. Organophosphates exert their effect by irreversibly binding to acetylcholinesterase (AChE) and, thus, can cause a cholinergic crisis. Administration of atropine will block the muscarinic sites, but it will not reactivate the enzyme, which will remain blocked for a long period of time. Therefore, it is essential to also administer pralidoxime as soon as possible to reactivate the enzyme before aging occurs. Administering pralidoxime alone will not protect the patient against the effects of acetylcholine resulting from AChE inhibition.

The potency of inhaled anesthetics is defined quantitatively as: A. Blood/gas partition coefficient. B. Cerebrovascular resistance. C. Minimum alveolar concentration. D. Volatility index. E. Sensitivity factor.

Correct answer = C. Potency of inhaled anesthetics is defined by MAC, equivalent to the median effective dose (ED50) of the anesthetic. Blood/gas partition coefficient determines solubility of the gas in blood. Cerebrovascular resistance is decreased by inhalation anesthetics. Volatility index and sensitivity factor are not terms associated with inhalation anesthetics.

Patient presents with salivation, lacrimation, urination and defecation as side effects of a medication. Which one of the following receptors mediates the actions of this drug? A. Nicotinic receptors. B. α Receptors. C. Muscarinic receptors. D. β Receptors.

Correct answer = C. The muscarinic receptors of the parasympathetic nervous system maintain essential body functions such as digestion and waste elimination. The nicotinic receptors are a receptor for acetylcholine. It plays a major role in skeletal muscles, ganglia and synthesis of catecholamines in the adrenal medulla. α and β receptors are receptors for norepinephrine and epinephrine and activation of these receptors does not produce these effects

Which one of the following is characteristic of parasympathetic stimulation? A. Decrease in intestinal motility. B. Inhibition of bronchial secretion. C. Contraction of sphincter muscle in the iris of the eye (miosis). D. Contraction of sphincter of urinary bladder. E. Increase in heart rate.

Correct answer = C. The parasympathetic nervous system is essential in maintenance activities, such as digestion and waste removal. Therefore, increased intestinal motility to facilitate peristalsis, relaxation of urinary bladder sphincters to cause urination, and increased bronchial secretions result. Increase in heart rate is a function of the sympathetic nervous system.

Which one of the following statements concerning the parasympathetic nervous system is correct? A. The parasympathetic system uses norepinephrine as a neurotransmitter. B. The parasympathetic system often discharges as a single, functional system. C. The parasympathetic division is involved in accommodation of near vision, movement of food, and urination. D. The postganglionic fibers of the parasympathetic division are long compared to those of the sympathetic nervous system. E. The parasympathetic system controls the secretion of the adrenal medulla.

Correct answer = C. The parasympathetic system maintains essential bodily functions, such as vision, movement of food, and urination. It uses acetylcholine, not norepinephrine, as a neurotransmitter, and it discharges as discrete fibers that are activated separately. The postganglionic fibers of the parasympathetic system are short compared to those of the sympathetic division. The adrenal medulla is under control of the sympathetic system

Local anesthetics A. Affect only small, unmyelinated nerve fibers. B. Have either a lipophilic or a hydrophilic group. C. Have either an amide or an ester linkage. D. Are unaffected by pH of the tissue and pKa of the drug. E. In their ionized form interact with the protein receptor of calcium channels.

Correct answer = C. The small, unmyelinated nerve fibers that conduct impulses for pain, temperature, and autonomic activity are most sensitive to the action of local anesthetics, but other nerve fibers are affected also. Local anesthetics have a lipophilic group, joined by either an amide or ester linkage to a carbon chain which, in turn, is joined to a hydrophilic group. Onset and duration of action of local anesthetics are influenced by both pH of the tissue and pKa of the drug. Local anesthetics work by blocking sodium ion channels

Recovery from IV induction agents is due to: A. Liver metabolism. B. Protein binding. C. Ionization. D. Redistribution from sites in the CNS. E. Plasma clearance.

Correct answer = D. Following initial flooding of the CNS with non-ionized molecules, the drug diffuses into other tissues. With secondary tissue uptake, plasma concentration falls, allowing the drug to diffuse out of the CNS. This initial redistribution of drug into other tissues leads to the rapid recovery seen after a single dose of an IV induction drug. Protein binding, ionization, and lipid solubility affect rate of transfer.

A patient with an acute attack of glaucoma is treated with pilocarpine. The primary reason for its effectiveness in this condition is its: A. Action to terminate acetylcholinesterase. B. Selectivity for nicotinic receptors. C. Ability to inhibit secretions, such as tears, saliva, and sweat. D. Ability to lower intraocular pressure. E. Inability to enter the brain.

Correct answer = D. Pilocarpine can abort an acute attack of glaucoma, because it causes pupillary constriction to lower intraocular pressure. It binds mainly to muscarinic receptors and can enter the brain. It is not effective in inhibiting secretions.

A 50-year-old male farm worker is brought to the emergency room. He was found confused in the orchard and since then has lost consciousness. His heart rate is 45, and his blood pressure is 80/40 mm Hg. He is sweating and salivating profusely. Which of the following treatments is indicated? A. Physostigmine. B. Norepinephrine. C. Trimethaphan. D. Atropine. E. Edrophonium.

Correct answer = D. The patient is exhibiting signs of cholinergic stimulation. Because he is a farmer, insecticide poisoning is a likely diagnosis. Thus, either intravenous or intramuscular doses of atropine are indicated to antagonize the muscarinic symptoms. Physostigmine and edrophonium are cholinesterase inhibitors and would exacerbate the problem. Norepinephrine would not be effective in combating the cholinergic stimulation. Trimethaphan, being a ganglionic blocker, would also worsen the condition

Which of the following is characteristic of the sympathetic nervous system? A. Discrete response to activation. B. Actions mediated by muscarinic and nicotinic receptors. C. Effects only mediated by norepinephrine. D. Responses predominate during physical activity or when experiencing fright. E. Subjected to voluntary control.

Correct answer = D. The sympathetic nervous system is activated by "fight or flight" stimuli. To achieve rapid activation of this system, the sympathetic nervous system often discharges as a unit. The receptors that mediate sympathetic nervous system effects on neuroeffector organs are α and β receptors. Because the sympathetic nervous system is a division of the autonomic nervous system, it is not subject to voluntary control and functions below conscious thought.

Which of the following statements about morphine is correct? A. It is used therapeutically to relieve pain caused by severe head injury. B. Its withdrawal symptoms can be relieved by naloxone. C. It causes diarrhea. D. It is most effective by oral administration. E. It rapidly enters all body tissues, including the fetus.

Correct answer = E. Morphine causes increased cerebrospinal fluid pressure secondary to dilation of cerebral vasculature and is contraindicated in severe head injury. Naloxone is an opioid antagonist and can precipitate withdrawal symptoms in morphine-addicted individuals. Morphine is administered parenterally, because absorption from the gastrointestinal tract is unreliable. It causes constipation.

Remedies for nasal stuffiness often contain which one of the following drugs? A. Albuterol. B. Atropine. C. Epinephrine. D. Norepinephrine. E. Phenylephrine.

Correct answer = E. Phenylephrine is an α1 agonist that constricts the nasal mucosa, thereby decreasing airway resistance. Norepinephrine and epinephrine also constrict the mucosa but have much too short a duration of action. Albuterol is a β2 agonist and has no effect on mucosal volume. Atropine, a muscarinic antagonist, only dries the mucosa but does not decrease its volume.

The drug of choice for treating decreased salivation accompanying head and neck irradiation is: A. Physostigmine. B. Scopolamine. C. Carbachol. D. Acetylcholine. E. Pilocarpine.

Correct answer = E. Pilocarpine, taken orally, has proven to be beneficial in this situation. All the others choices except scopolamine are cholinergic agonists. However, their ability to stimulate salivation is less than that of pilocarpine, and their other effects are more troublesome.

A dentist would like to reduce salivation in a patient in preparation for an oral surgical procedure. Which of the following strategies will be useful in reducing salivation? A. Activate nicotinic receptors in the salivary glands. B. Block nicotinic receptors in the salivary glands. C. Activate muscarinic receptors in the salivary glands. D. Block muscarinic receptors in the salivary glands.

D. Block muscarinic receptors in the salivary glands.

Which of the following drugs or classes of drugs will be useful in treating the symptoms of myasthenia gravis? A. Nicotinic antagonists. B. Muscarinic agonists. C. Muscarinic antagonists. D. Anticholinesterase agents.

D. Anticholinesterase agents.

Which medication is a glutamate receptor antagonist that can be used in combination with an acetylcholinesterase inhibitor to manage the symptoms of Alzheimer's disease? A. Rivastigmine. B. Ropinirole. C. Fluoxetine. D. Memantine. E. Donepezil

D. Memantine.

A 56-year-old patient who has suffered with severe chronic pain with radiculopathy secondary to spinal stenosis for years presents to the clinic for pain management. Over the years, this patient has failed to receive relief from the neuropathic pain from the radiculopathy with traditional agents such as tricyclics or anticonvulsants. Based on the mechanism of action, which opioid might be beneficial in this patient to treat both nociceptive and neuropathic pain? A. Meperidine. B. Oxymorphone. C. Morphine. D. Methadone

D. Methadone

Which of the following is a potent analgesic but a weak anesthetic? A. Etomidate. B. Halothane. C. Midazolam. D. Nitrous oxide. E. Thiopental.

D. Nitrous oxide

Which of the following determines the speed of recovery from intravenous anesthetics used for induction? A. Liver metabolism of the drug. B. Protein binding of the drug. C. Ionization of the drug. D. Redistribution of the drug from sites in the CNS. E. Plasma clearance of the drug.

D. Redistribution of the drug from sites in the CNS.

All of the following are correct regarding adrenergic receptors, except: A. α1 Receptors are primarily located on the postsynaptic membrane in the effector organs. B. α2 Receptors are primarily located on the presynaptic sympathetic nerve terminals. C. β1 Receptors are found mainly in the heart. D. β2 Receptors are found mainly in adipose tissue

D. β2 Receptors are found mainly in adipose tissue

Which of the following is correct regarding malignant hyperthermia? A. It is triggered by dantrolene. B. It is triggered by local anesthetics. C. It is generally mild and clinically insignificant. D. It has no familial component. E. It involves increased skeletal muscle oxidative metabolism.

E. It involves increased skeletal muscle oxidative metabolism.

A 54-year-old woman presented with signs and symptoms consistent with an early stage of rheumatoid arthritis. The decision was made to initiate NSAID therapy. Although the patient's disease was adequately controlled with an NSAID and methotrexate for some time, her symptoms began to worsen and radiologic studies of her hands indicated progressive destruction in the joints of several fingers. Treatment with another second-line agent for rheumatoid arthritis was considered. Which of the following is a parenterally administered DMARD whose mechanism of anti-inflammatory action is antagonism of tumor necrosis factor? (A) Cyclosporine (B) Etanercept (C) Penicillamine (D) Phenylbutazone (E) Sulfasalazine

Etanercept is a recombinant protein that binds to tumor necrosis factor and prevents its inflammatory effects. The answer is B.

Which drug is a full agonist at opioid receptors with analgesic activity equivalent to morphine, a longer duration of action, and fewer withdrawal signs on abrupt discontinuance than morphine? (A) Fentanyl (B) Hydromorphone (C) Methadone (D) Nalbuphine (E) Oxycodone

Fentanyl, hydromorphone, and methadone are full agonists with analgesic efficacy similar to that of morphine. When given intravenously, fentanyl has a duration of action of just 60-90 min. Hydromorphone has poor oral bioavailability. Methadone has the greatest bioavailability of the drugs used orally, and its effects are more prolonged. Tolerance and physical dependence develop, and dissipate, more slowly with methadone than with morphine. These properties underlie the use of methadone for detoxification and maintenance programs. The answer is C.

Mr Green, a 54-year-old banker, had a cardiac transplant 6 months ago. His current blood pressure is 120/70 mm Hg and heart rate is 100 bpm. Which of the following drugs would have the least effect on Mr Green's heart rate? (A) Albuterol (B) Epinephrine (C) Isoproterenol (D) Norepinephrine (E) Phenylephrine

Heart transplantation involves cutting of the autonomic nerves to the heart. As a result, autonomic nerve endings degenerate, and cardiac transmitter stores are absent for 2 years or longer after surgery. Therefore, indirect-acting sympathomimetics are ineffective in changing heart rate. All the drugs listed are direct-acting, and all but phenylephrine have significant effects on β receptors. Phenylephrine usually causes reflex bradycardia, which requires intact vagal innervation. The answer is E. (Note that denervation may result in upregulation of both β1 and β2 receptors so that direct-acting β agonists may have a greater than normal effect.)

A 23-year-old man has a pheochromocytoma, blood pressure of 190/120 mm Hg, and hematocrit of 50%. Pulmonary function and renal function are normal. His catecholamines are elevated, and he has a well-defined abdominal tumor on MRI. He has been scheduled for surgery. Which one of the following agents should be avoided in the anesthesia protocol? (A) Desflurane (B) Fentanyl (C) Isoflurane (D) Midazolam (E) Sevoflurane

Hepatitis after general anesthesia has been linked to use of halothane, although the incidence is very low (1 in 20,00-35,000). Hepatotoxicity has not been reported after administration of methoxyflurane or other inhaled anesthetics. However, fluoride release from prolonged use of methoxyflurane has caused renal insufficiency. The answer is D.

Total intravenous anesthesia with fentanyl has been selected for a frail elderly woman about to undergo cardiac surgery. Which statement about this anesthesia protocol is accurate? (A) Fentanyl will control the hypertensive response to surgical stimulation (B) Marked relaxation of skeletal muscles is anticipated (C) Opioids such as fentanyl provide useful cardiostimulatory effects (D) Patient awareness may occur during surgery, with recall after recovery (E) The patient is likely to experience pain during surgery

Intravenous opioids (eg, fentanyl) are widely used in anesthesia for cardiac surgery because they provide full analgesia and cause less cardiac depression than inhaled anesthetic agents. The opioids are not cardiac stimulants, and fentanyl is more likely to cause skeletal muscle rigidity than relaxation. Disadvantages of this technique are patient recall (which can be decreased by concomitant use of a benzodiazepine) and the occurrence of hypertensive responses to surgical stimulation. The addition of vasodilators (eg, nitroprusside) or a β blocker (eg, esmolol) may be needed to prevent intraoperative hypertension. The answer is D.

If ketamine is used as the sole anesthetic in the attempted reduction of a dislocated shoulder joint, its actions will include (A) Analgesia (B) Bradycardia (C) Hypotension (D) Muscle rigidity (E) Respiratory depression

Ketamine is a cardiovascular stimulant, increasing heart rate and blood pressure. This results in part from central sympathetic stimulation and from inhibition of norepinephrine reuptake at sympathetic nerve endings. Analgesia and amnesia occur, with preservation of muscle tone and minimal depression of respiration. The answer is A.

Prilocaine is relatively contraindicated in patients with cardiovascular or pulmonary disease because the drug (A) Acts as an agonist at β adrenoceptors in the heart and the lung (B) Causes decompensation through formation of methemo-globin (C) Inhibits cyclooxygenase in cardiac and pulmonary cells (D) Is a potent bronchoconstrictor (E) None of the above

Large doses of prilocaine may cause accumulation of o-toluidine, a metabolite that converts hemoglobin to methemoglobin. Patients may become cyanotic with blood "chocolate colored." High blood levels of methemoglobin have resulted in decompensation in patients who have cardiac or pulmonary diseases. The answer is B.

Which of the following drugs is most likely to increase serum concentrations of conventional doses of methotrexate, a weak acid that is primarily cleared in the urine? (A) Acetaminophen (B) Allopurinol (C) Colchicine (D) Hydroxychloroquine (E) Probenecid

Like other weak acids, methotrexate depends on active tubular excretion in the proximal tubule for efficient elimination. Probenecid competes with methotrexate for binding to the proximal tubule transporter and thereby decreases the rate of clearance of methotrexate. The answer is E.

All of the following factors influence the action of local anesthetics EXCEPT (A) Acetylcholinesterase activity in the region of the injection site (B) Blood flow through the tissue in which the injection is made (C) Dose of local anesthetic injected (D) The use of vasoconstrictors (E) Tissue pH

Local anesthetics are poor substrates for acetylcholinesterase, and the activity of this enzyme does not play a part in terminating the actions of local anesthetics. Ester-type local anesthetics are hydrolyzed by plasma (and tissue) pseudo- cholinesterases. Persons with genetically based defects in pseudocholinesterase activity are unusually sensitive to procaine and other esters. The answer is A.

Characteristic properties of local anesthetics include all of the following EXCEPT (A) An increase in membrane refractory period (B) Blockade of voltage-dependent sodium channels (C) Effects on vascular tone (D) Preferential binding to resting channels (E) Slowing of axonal impulse conduction

Local anesthetics bind preferentially to sodium channels in the open and inactivated states. Recovery from drug-induced block is 10-1000 times slower than recovery of channels from normal inactivation. Resting channels have a lower affinity for local anesthetics. The answer is D.

Actions and clinical uses of muscarinic cholinoceptor agonists include which one of the following? (A) Bronchodilation (treatment of asthma) (B) Miosis (treatment of glaucoma) (C) Decreased gastrointestinal motility (treatment of diarrhea) (D) Decreased neuromuscular transmission and relaxation of skeletal muscle (during surgical anesthesia) (E) Increased sweating (treatment of fever)

Muscarinic agonists cause accommodation and cyclospasm, the opposite of paralysis of accommodation (cycloplegia). In acute angle-closure glaucoma and chronic open-angle glaucoma, this may result in a desirable increased outflow of aqueous and decreased intraocular pressure. These agents may cause bronchospasm but have no effect on neuromuscular transmission. They may cause diarrhea and are not used in its treatment. Muscarinic agonists may also cause sweating, but drug-induced sweating is of no value in the treatment of fever. The answer is B.

A 20-year-old male patient scheduled for hernia surgery was anesthetized with halothane and nitrous oxide; tubocurarine was provided for skeletal muscle relaxation. The patient rapidly developed tachycardia and became hypertensive. Generalized skeletal muscle rigidity was accompanied by marked hyperthermia. Laboratory values revealed hyperkalemia and acidosis. This unusual complication of anesthesia is most likely to be caused by (A) Acetylcholine release from somatic nerve endings at skeletal muscle (B) Activation of brain dopamine receptors by halothane (C) Antagonism of autonomic ganglia by tubocurarine (D) Calcium released within skeletal muscle (E) Toxic metabolites of nitrous oxide

Malignant hyperthermia is a rare but life-threatening reaction that may occur during general anesthesia with halogenated anesthetics and skeletal muscle relaxants, particularly succinylcholine and tubocurarine. Release of calcium from skeletal sarcoplasmic reticulum leads to muscle spasms, hyperthermia and autonomic instability. Predisposing genetic factors include clinical myopathy associated with mutations in the gene loci for the skeletal muscle ryanodine receptor or L-type calcium receptors. Nitrous oxide is not metabolized! The answer is D

A 3-year-old child has been admitted to the emergency department having swallowed the contents of 2 bottles of a nasal decongestant. The active ingredient of the medication is a potent, selective α-adrenoceptor agonist drug. Which of the following is a sign of α-receptor activation that may occur in this patient? (A) Bronchodilation (B) Cardiac acceleration (tachycardia) (C) Pupillary dilation (mydriasis) (D) Renin release from the kidneys (E) Vasodilation of the blood vessels of the skin

Mydriasis can be caused by contraction of the radial fibers of the iris; these smooth muscle cells have α receptors. All the other listed responses are mediated by β adrenoceptors (Table 6-4). The answer is C.

A patient is to receive epinephrine. She has previously received an adrenoceptor-blocking agent. Which of the following effects of epinephrine would be blocked by phentolamine but not by metoprolol? (A) Cardiac stimulation (B) Increase of cAMP (cyclic adenosine monophosphate) in fat (C) Mydriasis (D) Relaxation of bronchial smooth muscle (E) Relaxation of the uterus

Mydriasis caused by contraction of the pupillary dilator radial smooth muscle is mediated by α receptors. All the other effects listed are mediated by β receptors. The answer is C.

Which statement about the speed of onset of nerve blockade with local anesthetics is correct? (A) Faster in hypercalcemia (B) Faster in myelinated fibers (C) Faster in tissues that are infected (D) Slower in hyperkalemia (E) Slower in the periphery of a nerve bundle than in the center of a bundle

Myelinated nerve fibers are blocked by local anesthetics more readily than unmyelinated ones. See the Skill Keeper answer for an explanation of the effects of hypocalcemia and hyperkalemia on nerve blockade by local anesthetics. The answer is B.

Full activation of the parasympathetic nervous system is likely to produce which of the following effects? (A) Bronchodilation (B) Decreased intestinal motility (C) Increased thermoregulatory sweating (D) Increased pupillary constrictor tone (miosis) (E) Increased heart rate (tachycardia)

Parasympathetic discharge causes bronchial and intestinal smooth muscle contraction and bradycardia. Thermoregulatory (eccrine) sweat glands are innervated by sympathetic cholinergic fibers, not parasympathetic. The answer is D.

When given to a patient, phentolamine blocks which one of the following? (A) Bradycardia induced by phenylephrine (B) Bronchodilation induced by epinephrine (C) Increased cardiac contractile force induced by norepinephrine (D) Miosis induced by acetylcholine (E) Vasodilation induced by isoproterenol

Phenylephrine, an α agonist, increases blood pressure and causes bradycardia through the baroreceptor reflex. Blockade of this drug's α-mediated vasoconstrictor effect prevents the bradycardia. The answer is A.

Which one of the following drugs has a very high affinity for the phosphorus atom in parathion and is often used to treat life-threatening insecticide toxicity? (A) Atropine (B) Benztropine (C) Bethanechol (D) Botulinum (E) Cyclopentolate (F) Neostigmine (G) Pralidoxime

Pralidoxime has a very high affinity for the phosphorus atom in organophosphate insecticides. The answer is G.

A young male patient is brought to the emergency department in an anxious and agitated state. He informs the attending physician that he uses "street drugs" and that he gave himself an intravenous "fix" approximately 12 h ago. He now has chills and muscle aches and has also been vomiting. His symptoms include hyperventilation and hyperthermia. The attending physician notes that his pupil size is larger than normal. Which drug will be most effective in alleviating the symptoms experienced by this patient? (A) Buprenorphine (B) Codeine (C) Methadone (D) Naltrexone (E) Tramadol

Prevention of signs and symptoms of withdrawal after chronic use of a strong opiate like heroin requires replacement with another strong opioid analgesic drug. Methadone is most commonly used, but other strong μ-receptor agonists would also be effective. Acetaminophen and codeine will not be effective. Beneficial effects of diazepam are restricted to relief of anxiety and agitation. The antagonist drug naltrexone may exacerbate withdrawal symptoms. The answer is C.

Postoperative vomiting is uncommon with this intravenous agent, and patients are often able to ambulate sooner than those who receive other anesthetics. (A) Enflurane (B) Etomidate (C) Midazolam (D) Propofol (E) Thiopental

Propofol is used extensively in anesthesia protocols, including those for day surgery. The favorable properties of the drug include an antiemetic effect and recovery more rapid than that after use of other intravenous drugs. Propofol does not cause cumulative effects, possibly because of its short half-life (2-8 min) in the body. The drug is also used for prolonged sedation in critical care settings. The answer is D.

A crop duster pilot has been accidentally exposed to a high concentration of a highly toxic agricultural organophosphate insecticide. If untreated, the cause of death from such exposure would probably be (A) Cardiac arrhythmia (B) Gastrointestinal bleeding (C) Heart failure (D) Hypotension (E) Respiratory failure

Respiratory failure, from neuromuscular paralysis or CNS depression, is the most important cause of acute deaths in cholinesterase inhibitor toxicity. The answer is E.

A 16-year-old girl comes to the emergency department suffering from the effects of an aspirin overdose. Which of the following syndromes is this patient most likely to exhibit as a result of this drug overdose? (A) Bone marrow suppression and possibly aplastic anemia (B) Fever, hepatic dysfunction, and encephalopathy (C) Hyperthermia, metabolic acidosis, and coma (D) Rapid, fulminant hepatic failure (E) Rash, interstitial nephritis, and acute renal failure

Salicylate intoxication is associated with metabolic acidosis, dehydration, and hyperthermia. If these problems are not corrected, coma and death ensue. The answer is C.

Which statement about abuse of the opioid analgesics is false? (A) Lacrimation, rhinorrhea, yawning, and sweating are early signs of withdrawal from opioid analgesics (B) In withdrawal from opioids, clonidine may be useful in reducing symptoms caused by sympathetic overactivity (C) Methadone alleviates most of the symptoms of heroin withdrawal (D) Most patients experiencing withdrawal from heroin are free of the symptoms of abstinence in 6-8 d (E) Naloxone may precipitate a severe withdrawal state in abusers of opioid analgesics with symptoms starting in less than 15-30 min

Symptoms of opioid withdrawal usually begin within 6-8 h, and the acute course may last 6-8 d. However, a secondary phase of heroin withdrawal, characterized by bradycardia, hypotension, hypothermia, and mydriasis, may last 26-30 wk. Methadone is commonly used in detoxification of the heroin addict because it is a strong agonist, has high oral bioavailability, and has a relatively long half-life. The answer is D.

A 27-year old compulsive drug user injected a drug he thought was methamphetamine, but he has not developed any signs of methamphetamine action. He has been admitted to the emergency department and antimuscarinic drug overdose is suspected. Probable signs of atropine overdose include which one of the following? (A) Gastrointestinal smooth muscle cramping (B) Increased heart rate (C) Increased gastric secretion (D) Pupillary constriction (E) Urinary frequency

Tachycardia is a characteristic atropine overdose effect. Bradycardia is sometimes observed after small doses. None of the other choices are typical of atropine or methamphetamine overdose. The answer is B.

Muscle rigidity can be a side effect of which intravenous anesthetic? (A) fentanyl (B) midazolam (C) ketamine (D) propofol (E) thiopental

The answer is A: fentanyl. Fentanyl is a potent opioid agonist given as part of balanced anesthesia. It can cause chest wall (truncal) rigidity because of interactions in the striatum. This effect has not been noted for B, midazolam, C, ketamine, D, propofol, or E, thiopental.

Which drug is most likely to slow recovery from hypoglycemia in a diabetic patient who has taken an excessive dose of insulin? (A) metoprolol (B) doxazosin (C) propranolol (D) phenoxybenzamine (E) atenolol

The answer is C: propranolol. Nonselective β-blockers such as propranolol are most likely to inhibit β2-receptor- mediated glycogenolysis and slow recovery from hypoglycemia. Selective β1-blockers such as atenolol and metoprolol are less likely to inhibit glycogenolysis than nonselective blockers, and α-adrenoceptor blockers such as doxazosin and phentolamine are least likely to impair glycogenolysis.

After being stung by a bee, a woman experiences urticaria, laryngeal edema, difficult breathing, and hypotension. She receives oxygen and administration of an adrenoceptor agonist. Which action would lead to bronchodilation? (A) increased cAMP levels (B) increased cyclic guanosine monophosphate (cGMP) levels (C) increased IP3 levels (D) calcium influx (E) sequestration of calcium

The answer is A: increased cAMP levels. The preferred treatment for severe hypersensitivity reactions (anaphylaxis) is epinephrine. The drug causes bronchodilation by activation of β2-adrenoceptors in bronchial smooth muscle, leading to increased cAMP levels and smooth muscle relaxation. Although cGMP (B) also mediates smooth muscle relaxation, levels of this substance are not significantly increased by β2-adrenoceptor activation. Increased IP3 levels (C) causes smooth muscle contraction, as will calcium influx (D). Sequestration of calcium (E) causes muscle relaxation, but this action is not invoked by β2-receptor stimulation.

Selegiline, an antidepressant also used for the treatment of Parkinson disease, has which one of the following mechanisms of action? (A) it is a selective MAO-B inhibitor (B) it blocks the reuptake of dopamine (C) it irreversibly binds to COMT (D) it increases release of dopamine vesicles (E) it blocks muscarinic cholinergic receptors

The answer is A: it is a selective MAO-B inhibitor. Selegiline retards the progress of parkinsonism by inhibiting the formation of free radicals from the action of MAO-B on dopamine. Answer B, it blocks the reuptake of dopamine, would be a possible treatment, but no drug like this has been tried in the treatment of parkinsonism. Answer C, it irreversibly binds to COMT, may cause increased dopamine, but this is not the mechanism of selegiline. Answer D, it increases release of dopamine vesicles, is the mechanism of amantadine. Answer E, it blocks muscarinic cholinergic receptors, is the mechanism of anticholinergic agents used for the treatment of parkinsonism.

In a case of an opioid overdose, naloxone can be given in repeated doses because of which property of naloxone? (A) may have a shorter half-life than the opioid agonist (B) is effective only at high cumulative doses (C) is needed to stimulate the respiratory center (D) is safe only in extremely small doses (E) is only a partial opioid agonist

The answer is A: may have a shorter half-life than the opioid agonist. Treatment of opioid overdose often requires repeated doses of naloxone or continuous infusion to compete with the agonist at the receptor. Answer B, is effective only at high cumulative doses, is not true, and even the first dose of naloxone may provide miraculous reversal of opioid overdose. Answers C through E are not true.

Epinephrine is sometimes added to commercial local anesthetic solutions for which purpose? (A) to decrease the rate of absorption of the local anesthetic (B) to decrease the duration of action of the local anesthetic (C) to block the metabolism of ester-type local anesthetics (D) to enhance the distribution of the local anesthetic (E) to act synergistically with the local anesthetic at the nerve ion channel

The answer is A: to decrease the rate of absorption of the local anesthetic. Epinephrine causes vasoconstriction acting at α1 receptors and thus decreases the amount of systemic absorption of the local anesthetic. Answer B, to decrease the duration of action of the local anesthetic, is wrong because epinephrine actually prolongs the duration of action by reducing absorption away from the nerve fiber. Answer C, to block the metabolism of ester-type local anesthetics, and E, to act synergistically with local anesthetic at the nerve ion channel, are wrong because no evidence exists for epinephrine having this effect. Answer D, to enhance the distribution of local anesthetic, is incorrect because epinephrine affects the pharmacokinetic property of absorption directly.

Local anesthetics exert their effects by which one of the following mechanisms? (A) increasing K+ conductance and hyperpolarizing nerves (B) blocking the Na+ channels in nerves (C) inactivating the Na+,K+-adenosine triphosphatase (ATPase) pump (D) blocking excitation at postsynaptic receptors (E) blocking by a direct action only at the synapse

The answer is B: blocking the Na+ channels in nerves. Local anesthetics produce a block of voltage-gated sodium channels needed to conduct action potentials along nerve fibers. The unprotonated form of the local anesthetic molecule passes through the neuronal membrane and is changed to the protonated form in the cytoplasm. This form then binds to the inside of the sodium channel protein. Answer A, increasing K+ conductance and hyperpolarizing nerves, would cause inhibition of firing but not total blockade of action potentials because they are not dependent on potassium channels for nerve fiber conduction. Answer C, inactivating the Na+ ,K+ - adenosine triphosphatase (ATPase) pump, is the action of some cardiovascular agents used for congestive heart failure. Answer D, blocking excitation at postsynaptic receptors, is the action of a receptor antagonist. Answer E, blocking by a direct action only at the synapse, again, is not the action of an local anesthetic, which can block all along the nerve fiber.

Toxic doses of scopolamine would be expected to cause all of the following effects EXCEPT (A) hallucinations (B) bronchospasm (C) hyperthermia (D) urinary retention (E) blurred vision

The answer is B: bronchospasm. Muscarinic blockers such as atropine and scopolamine cause relaxation of bronchial smooth muscle and bronchodilation. These drugs may also cause hyperthermia by inhibiting sweating, thereby leading to vasodilation and flushing. Scopolamine causes blurred vision by relaxing the ciliary muscle, thereby producing cycloplegia (paralysis of accommodation).

A man is arrested while using a substance that inhibits the catecholamine transporter in the neuronal membrane. Which sign would most likely be observed in this person? (A) excessive sweating (B) dilation of the pupils (C) involuntary muscle contractions (D) flushing of the skin (E) sedation

The answer is B: dilation of the pupils. Cocaine inhibits the catecholamine transporter and increases the synaptic concentration of norepinephrine, leading to the activation of adrenoceptors in peripheral tissues and the central nervous system. Norepinephrine activates α1adrenoceptors in the iris dilator muscle, thereby causing muscle contraction and pupillary dilation. Excessive sweating (answer A) would result from activation of muscarinic receptors in sweat glands, whereas involuntary muscle contractions (answer C) would result from nicotinic receptor stimulation. Flushing of the skin (answer D) and sedation (answer E) are not typically caused by adrenoceptor or acetylcholine receptor activation.

Which property is characteristic of the sympathetic nervous system? (A) discrete activation of specific organs (B) long preganglionic neurons (C) action terminated by cholinesterase (D) inhibits the enteric nervous system (E) activated by increased arterial blood pressure

The answer is D: inhibits the enteric nervous system. Answers A, B, C, and E (discrete activation of specific organs, long preganglionic neurons, action terminated by cholinesterase, activated by increased arterial blood pressure) are attributes of the parasympathetic nervous system.

A man receives an injection of epinephrine to treat an allergic reaction to a bee sting. Which effect would result from this treatment? (A) increased glucose absorption from the gut (B) increased hepatic output of glucose (C) increased uptake of glucose by skeletal muscle (D) increased formation of glycogen (E) increased conversion of glucose to fat

The answer is B: increased hepatic output of glucose. Epinephrine activates β2-adrenoceptors in the liver and thereby increases the breakdown of glycogen and formation of glucose (glycogenolysis). Epinephrine does not increase glucose absorption (answer A), glucose uptake (answer C), glycogen formation (answer D), or conversion of glucose to fat (answer E).

Which of the following characteristics is used to quantitate and compare the potency of gaseous general anesthetics? (A) blood:gas partition coefficient (B) minimal alveolar concentration (C) blood:brain partition coefficient (D) rate of uptake and elimination (E) relative analgesic potency

The answer is B: minimal alveolar concentration. The minimal alveolar concentration value, which is used for inhalational agents to determine potency, is defined as the percent concentration in the administered air that produces no response to surgical incision in 50% of the subjects. Answers A, C, and D are measures of the characteristics of anesthetics but do not give the potency. Answer E, relative analgesic potency, is a term used when comparing analgesic agents.

Which one of the following inhalational anesthetics can provide anesthetic effectiveness only under hyperbaric conditions? (A) enflurane (B) nitrous oxide (C) halothane (D) methoxyflurane (E) isoflurane

The answer is B: nitrous oxide. Although nitrous oxide has the fastest rate of induction and is safe to use, the potency is such that one would have to administer the gas under hyperbaric conditions for it to be the sole inhalational agent. It is often used in dental procedures for its analgesic effects and as an adjunct in other procedures.

A child with asthma is being treated with an adrenoceptor agonist to prevent bronchospasm. Which side effect is typically associated with this drug? (A) sedation (B) rapid heart rate (C) muscle weakness (D) low blood pressure (E) blurred vision

The answer is B: rapid heart rate. β2-Adrenoceptor agonists such as albuterol are used to relax bronchial smooth muscle and prevent bronchospasm in persons with asthma. These drugs also activate β-adrenoceptors in the heart and increase heart rate, but do not typically cause low blood pressure, blurred vision, sedation, or muscle weakness.

Cardiac arrhythmias after initial doses of levodopa (ldopa) are occasionally observed. Which of the following most likely explains this occurrence? (A) direct action on cardiac dopamine receptors (B) decreased release of catecholamines (C) direct β-adrenoceptor stimulation (D) increased release of dopamine (E) interaction with vagal cholinergic receptors

The answer is C: direct β-adrenoceptor stimulation. Metabolism of l-dopa in the periphery to dopamine can lead to cardiac arrhythmias by direct action of dopamine on cardiac β-adrenoceptors. Administration of l-dopa with carbidopa will decrease the formation of dopamine in the periphery and decrease the likelihood of cardiac abnormalities. Answer A, direct action on cardiac dopamine receptors, may be a possible mechanism if there were significant dopamine receptors in the heart modulating cardiac rhythm, but there are not. Answer B, decreased release of catecholamines, would decrease cardiac stimulation. Answer D, increased release of dopamine, is not the best answer because increased peripheral formation is not the same as increased neuronal release. Answer E, interaction with vagal cholinergic receptors, might affect cardiac function, but dopamine or l-dopa has no interaction with cholinergic receptors.

A woman with facial muscle spasms is treated with an agent that inhibits the release of acetylcholine. Which side effect is most likely to occur in this patient? (A) bradycardia (B) urinary incontinence (C) dry mouth (D) diarrhea (E) constriction of the pupils

The answer is C: dry mouth. Botulinum toxin inhibits the release of acetylcholine from cholinergic neurons, and it is used to inhibit neuromuscular transmission in persons with dystonia. The drug may also inhibit acetylcholine release from parasympathetic nerves and cause dry mouth and dysphagia, particularly when it is administered to the head and neck. Bradycardia, urinary incontinence, diarrhea, and miosis are effects that would be caused by increased release of acetylcholine from parasympathetic nerves.

An agricultural worker is brought to the emergency department after abrupt onset of bowel and bladder incontinence and muscle weakness. He is given oxygen and antidotal drug treatments. Which drug mechanism would increase muscle strength in this patient? (A) blockade of muscarinic receptors (B) activation of nicotinic receptors (C) increased neurotransmitter degradation (D) induction of drug-metabolizing enzymes (E) increased urinary excretion of weak acids

The answer is C: increased neurotransmitter degradation. The patient has signs and symptoms of organophosphate toxicity that are caused by inhibition of cholinesterase and excessive stimulation of muscarinic and nicotinic receptors by acetylcholine. The treatment of organophosphate intoxication includes administration of pralidoxime, which reactivates cholinesterase and leads to increased acetylcholine degradation. The patient's muscle weakness is caused by prolonged depolarization of skeletal muscle. Activation of nicotinic receptors (B) would increase depolarization and muscle weakness.

Anticholinergic agents are useful in the treatment of parkinsonism because of which one of the following mechanisms? (A) decreased levels of acetylcholine from loss of neurons (B) continuing degeneration of dopamine neurons (C) neurotransmitter imbalance in the basal ganglia (D) increased activity of acetylcholinesterase (E) increased release of dopamine in basal ganglia

The answer is C: neurotransmitter imbalance in the basal ganglia. The decrease of dopamine projections to the striatum results in a relative abundance of acetylcholine activity in the striatum. Acetylcholine (muscarinic) antagonists rebalance this abnormality. Answer A, decreased levels of acetylcholine from loss of neurons, would not be a reason to give an antagonist to correct this condition. Answer B, the continuing degeneration of dopamine neurons, is a fact of the progression of the disease state, but antimuscarinic agents do not retard the progression of parkinsonism. Answer D, increased activity of acetylcholinesterase, is not correct because no evidence of enzyme up-regulation in parkinsonism exists. Answer E, increased release of dopamine in basal ganglia, is clearly wrong because the disease is caused by the degeneration of dopamine neurons.

A man with episodic severe hypertension is found to have markedly elevated levels of epinephrine and norepinephrine metabolites in his urine and requires a long-acting drug to lower blood pressure before surgery. (A) alfuzosin (B) carvedilol (C) betaxolol (D) phenoxybenzamine (E) phentolamine

The answer is D: phenoxybenzamine. The patient most likely has a tumor of the adrenal medulla called pheochromocytoma. This tumor secretes massive quantities of epinephrine and norepinephrine, thereby causing severe hypertension. Phenoxybenzamine is a noncompetitive, long-acting α-adrenoceptor antagonist that is sometimes used to reduce blood pressure in patients with this condition.

Topical ocular administration of tropicamide will cause (A) contraction of the ciliary muscle (B) vasoconstriction (C) miosis (D) relaxation of the iris sphincter muscle (E) lacrimation

The answer is D: relaxation of the iris sphincter muscle. Tropicamide binds to muscarinic receptors and competitively blocks acetylcholine released by the parasympathetic oculomotor nerve. This action leads to relaxation of the iris sphincter muscle and dilation of the pupil (mydriasis), thereby facilitating ophthalmoscopic examination of the peripheral retina

Which drug produces transient muscle fasciculations followed by muscle paralysis that is not reversed by neostigmine? (A) rocuronium (B) hyoscyamine (C) cisatracurium (D) succinylcholine (E) pancuronium

The answer is D: succinylcholine. Succinylcholine is the only depolarizing neuromuscular blocking agent that produces persistent depolarization of the motor end plate, thereby causing transient muscle fasciculations followed by paralysis. Cholinesterase inhibitors, acting to increase acetylcholine levels, do not counteract the muscle paralysis produced by succinylcholine and can actually increase the degree of paralysis by prolonging muscle depolarization.

Most clinically used opioid analgesics are selective for which type of opioid receptor? (A) κ (kappa) (B) α (alpha) (C) β (beta) (D) µ (mu) (E) δ (delta)

The answer is D: µ (mu) receptors. Although there are three homologous opioid receptor proteins, most clinical opioid analgesics are agonists at the µ receptors. Answer A, κ (kappa), is also a type of opioid receptor that can mediate analgesia but plays only a minor role in the action of some mixed agonist-antagonist opioids. Answer B, α (alpha), is part of the adrenoceptor family. Answer C, β (beta), is a type of adrenoceptor. Answer E, δ (delta), is also a type of opioid receptor and does mediate analgesia in preclinical models, but δ-selective agents have not surfaced in the clinic.

Which of the following opioids is so lipophilic that it is marketed in a skin patch used to treat chronic pain? (A) morphine (B) naltrexone (C) scopolamine (D) methadone (E) fentanyl

The answer is E: fentanyl. This potent opioid is available as a transdermal patch for the treatment of chronic pain. Answer A, morphine, is not so lipophilic to allow transdermal administration. Answer B, naltrexone, is an opioid antagonist that does come in a patch formulation but would not help with chronic pain. It is used to treat opioid and alcohol dependence. Answer C, scopolamine, does also come in a patch but is used for motion sickness. Answer D, methadone, is a long-acting opioid agonist but is not available in a patch.

The fact that the degree of reinforcement for morphine is less than that of heroin is best explained by which one of the following statements? (A) morphine is a partial agonist (B) heroin binds more tightly to opioid receptors (C) morphine is metabolized faster than heroin (D) morphine is first metabolized to heroin (E) heroin is distributed more rapidly to the brain

The answer is E: heroin is distributed more rapidly to the brain. Heroin is an illicit opioid made by the addition of two acetyl groups at the 3 and 6 position of the morphine molecule. Because of this, diacetylmorphine (heroin) is more lipophilic and crosses the blood-brain barrier quite rapidly to exert its reinforcing effects. Although answer A, morphine is a partial agonist, and answer B, heroin binds more tightly to opioid receptors, are wrong, answer C, morphine is metabolized faster than heroin, may be generally true because heroin has extra groups to demethylate, but the degree of reinforcement is greater with more rapidly acting agents. Answer D, morphine is first metabolized to heroin, is simply wrong.

Which of the following statements best explains the observation that morphine is more likely to cause nausea and vomiting in ambulatory patients? (A) morphine inhibits chemoreceptor trigger zone neurons (B) morphine sensitizes medulla cough center neurons (C) opioids cause sedation, which makes walking more difficult (D) patients on opioids eat more (E) opioids increase vestibular sensitivity

The answer is E: opioids increase vestibular sensitivity. Ambulatory patients report more instances of nausea and vomiting than recumbent patients administered morphine. In vitro studies show that opioids modulate the inner ear vestibular complex to increase its sensitivity. Answers A, morphine inhibits chemoreceptor trigger zone neurons, and B, morphine sensitizes medulla cough center neurons, are both wrong because morphine has the opposite effects and stimulates the chemoreceptor trigger zone neurons in the medulla and inhibits cough center neurons. Answer C, opioids cause sedation, which makes walking more difficult, may be true but does not affect the onset of nausea and vomiting. Answer D, patients on opioids eat more, has no support from the literature, although fasting does appear to increase endogenous opioid peptides in the CNS and has been implicated in the pathology of the eating disorder anorexia nervosa.

A woman experiences pain and ischemia in her finger after accidentally injecting it with an autoinjector that she carries for emergency treatment for allergic reactions. (A) alfuzosin (B) carvedilol (C) betaxolol (D) phenoxybenzamine (E) phentolamine

The answer is E: phentolamine. Epinephrine and other adrenoceptor agonists can cause excessive vasoconstriction and ischemia when injected into fingers, toes, or other tissues as a result of activating α1-adrenoceptors in vascular smooth muscle. Phentolamine is a nonselective α-adrenoceptor antagonist that can be injected directly into affected tissues to counteract the vasoconstrictive effects of adrenoceptor agonists.

Which of the following is not a mechanism of action for antiparkinsonism agents? (A) direct dopamine agonist (B) precursor loading (C) dopamine metabolism inhibition (D) cholinergic receptor blocking (E) selective dopamine reuptake inhibition

The answer is E: selective dopamine reuptake inhibition. Although this mechanism of action would be beneficial in the treatment of parkinsonism because it would lead to an increase in synaptic levels of dopamine, no such agents are currently available. Answer A, direct dopamine agonist, is a mechanism used by dopamine agonists such as bromocriptine. Answer B, precursor loading, is the mechanism of l-dopa. Answer C, dopamine metabolism inhibition, is used by selegiline. Answer D, cholinergic receptor blocking, is a mechanism also used for the treatment of parkinsonism by such agents as benztropine

A 20-year-old male patient scheduled for hernia surgery was anesthetized with halothane and nitrous oxide; tubocurarine was provided for skeletal muscle relaxation. The patient rapidly developed tachycardia and became hypertensive. Generalized skeletal muscle rigidity was accompanied by marked hyperthermia. Laboratory values revealed hyperkalemia and acidosis. The patient should be treated immediately with (A) Atropine (B) Baclofen (C) Dantrolene (D) Edrophonium (E) Flumazenil

The drug of choice in malignant hyperthermia is dantrolene, which prevents release of calcium from the sarcoplasmic reticulum of skeletal muscle cells. Appropriate measures must be taken to lower body temperature, control hypertension, and restore acid-base and electrolyte balance. The answer is C.

A group of volunteers are involved in a phase 1 clinical trial of a new autonomic drug. When administered by intravenous bolus, the blood pressure increases. When given orally for 1 week, the blood pressure decreases. Which of the following standard agents does the new drug most resemble? (A) Atropine (B) Clonidine (C) Phentolamine (an α blocker) (D) Phenylephrine (E) Propranolol (a β blocker)

The dual blood pressure effects of the drug suggest that initially it is causing a direct α-agonist vasoconstrictor effect, but when given for a week, it is accumulating in a blood pressure-controlling center, eg, the CNS, and reducing sympathetic outflow. The answer is B.

Which drug does not activate opioid receptors, has been proposed as a maintenance drug in treatment programs for opioid addicts, and with a single oral dose, will block the effects of injected heroin for up to 48 h? (A) Fentanyl (B) Nalbuphine (C) Naloxone (D) Naltrexone (E) Propoxyphene

The opioid antagonist naltrexone has a much longer half-life than naloxone, and its effects may last 2 d. A high degree of client compliance would be required for naltrexone to be of value in opioid dependence treatment programs. The same reservation is applicable to the use of naltrexone in alcoholism. The answer is D.

A young male patient is brought to the emergency department in an anxious and agitated state. He informs the attending physician that he uses "street drugs" and that he gave himself an intravenous "fix" approximately 12 h ago. He now has chills and muscle aches and has also been vomiting. His symptoms include hyperventilation and hyperthermia. The attending physician notes that his pupil size is larger than normal. What is the most likely cause of these signs and symptoms? (A) The patient had injected dextroamphetamine (B) The patient has hepatitis B (C) The patient has overdosed with an opioid (D) The signs and symptoms are those of the opioid abstinence syndrome (E) These are early signs of toxicity due to contaminants in "street heroin"

The signs and symptoms are those of withdrawal in a patient physically dependent on an opioid agonist. They usually start within 6-10 h after the last dose; their intensity depends on the degree of physical dependence, and peak effects usually occur at 36-48 h. Mydriasis is a prominent feature of the abstinence syndrome; other symptoms include rhinorrhea, lacrimation, piloerection, muscle jerks, and yawning. The answer is D.

A 7-year-old boy with a previous history of bee sting allergy is brought to the emergency department after being stung by 3 bees. If this child has signs of anaphylaxis, what is the treatment of choice? (A) Diphenhydramine (an antihistamine) (B) Ephedrine (C) Epinephrine (D) Isoproterenol (E) Methylprednisolone (a corticosteroid)

The treatment of anaphylaxis requires a powerful physiologic antagonist with the ability to cause rapid bronchodilation (β2 effect), and vasoconstriction (α effect). Epinephrine is the most effective agent with these properties. Antihistamines and corticosteroids are sometimes used as supplementary agents, but the prompt parenteral use of epinephrine is mandatory. The answer is C.

Which one of the following is the primary neurotransmitter agent normally released in the sinoatrial node of the heart in response to a blood pressure increase? (A) Acetylcholine (B) Dopamine (C) Epinephrine (D) Glutamate (E) Norepinephrine

When blood pressure increases, the parasympathetic system is activated and heart rate decreases. Acetylcholine is the transmitter at parasympathetic nerve endings innervating the sinus node (nerve endings of the vagus nerve). The answer is A.