Katzung Practice Questions
A patient underwent a surgical procedure of 2 h. Anesthesia was provided by isoflurane, supplemented by intravenous midazolam and a nondepolarizing muscle relaxant. At the end of the procedure, a low dose of atropine was administered followed by pyridostigmine. 2. The main reason for administering atropine was to (A) Block cardiac muscarinic receptors (B) Enhance the action of pyridostigmine (C) Prevent spasm of gastrointestinal smooth muscle (D) Provide postoperative analgesia (E) Reverse the effects of the muscle relaxant
A Acetylcholinesterase inhibitors used for reversing the effects of nondepolarizing muscle relaxants cause increases in ACh at all sites where it acts as a neurotransmitter. To offset the resulting side effects, including bradycardia, a muscarinic blocking agent is used concomitantly. Although atropine is effective, glycopyrollate is usually preferred because it lacks CNS effects.
A 40-year-old woman has sporadic attacks of intense anxiety with marked physical symptoms, including hyperventilation, tachycardia, and sweating. If she is diagnosed as suffering from a panic disorder, the most appropriate drug to use is (A) Alprazolam (B) Eszopiclone (C) Flurazepam (D) Propranolol (E) Ramelteon
A Alprazolam and clonazepam (not listed) are the most effective of the benzodiazepines for the treatment of panic disorders. Eszopiclone and flumazenil are hypnotics. Propranolol is commonly used to attenuate excessive sympathomimetic activity in persons who suffer from performance anxiety ("stage fright").
Regarding the spasmolytic drugs, which of the following statements is not accurate? (A) Baclofen acts on GABA receptors in the spinal cord to increase chloride ion conductance (B) Cyclobenzaprine decreases both oropharyngeal secretions and gut motility (C) Dantrolene has no significant effect on the release of calcium from cardiac muscle (D) Diazepam causes sedation at doses commonly used to reduce muscle spasms (E) Intrathecal use of baclofen is effective in some refractory cases of muscle spasticity
A Baclofen activates GABAB receptors in the spinal cord. However, these receptors are coupled to K+ channels. GABAA receptors in the CNS modulate chloride ion channels, an action facilitated by diazepam and other benzodiazepines.
A 16-year-old girl has paroxysmal attacks of rapid heart rate with palpitations and shortness of breath. These episodes occasionally terminate spontaneously but often require a visit to the emergency department of the local hospital. Her ECG during these episodes reveals an AV nodal tachycardia. The antiarrhythmic of choice in most cases of acute AV nodal tachycardia is (A) Adenosine (B) Amiodarone (C) Flecainide (D) Propranolol (E) Verapamil
A Calcium channel blockers are effective in supraventricular AV nodal tachycardias. However, adenosine is just as effective in most acute nodal tachycardias and is less toxic because of its extremely short duration of action.
A man is admitted to the emergency department with a brownish cyanotic appearance, marked shortness of breath, and hypotension. Which of the following is most likely to cause methemoglobinemia? (A) Amyl nitrite (B) Isosorbide dinitrate (C) Isosorbide mononitrate (D) Nitroglycerin (E) Sodium cyanide
A Nitrites, not nitrates, cause methemoglobinemia in adults. Methemoglobinemia is delibrately induced in one of the treatments of cyanide poisoning
If a β blocker were to be used for prophylaxis in this patient, what is the most probable mechanism of action in angina? (A) Block of exercise-induced tachycardia (B) Decreased end-diastolic ventricular volume (C) Increased double product (D) Increased cardiac force (E) Decreased ventricular ejection time
A Propranolol blocks tachycardia but has none of the other effects listed. Only revascularization increases double product; drugs that decrease cardiac work increase exercise time by decreasing double product.
Which of the following has been shown to prolong life in patients with chronic congestive failure in spite of having a negative inotropic effect on cardiac contractility? (A) Carvedilol (B) Digoxin (C) Dobutamine (D) Enalapril (E) Furosemide
A Several β blockers, including carvedilol, have been shown to prolong life in heart failure patients even though these drugs have a negative inotropic action on the heart. Their benefits presumably result from some other effect, and at least one β blocker has failed to show a mortality benefit.
Myalgias are a common postoperative complaint of patients who receive large doses of succinylcholine, possibly the result of muscle fasciculations caused by depolarization. Which drug administered in the operating room can be used to prevent postoperative pain caused by succinylcholine? (A) Atracurium (B) Baclofen (C) Dantrolene (D) Diazepam (E) Lidocaine
A The depolarizing action of succinylcholine at the skeletal muscle end plate can be antagonized by small doses of nondepolarizing blockers. To prevent skeletal muscle fasciculations and the resulting postoperative pain caused by succinylcholine, a small nonparalyzing dose of a nondepolarizing drug (eg, atracurium) is often given immediately before succinylcholine.
A 5-year-old child was vomiting and was brought to the emergency department with sinus arrest and a ventricular rate of 35 bpm. An empty bottle of his uncle's digoxin was found where he was playing. Which of the following is the drug of choice in treating a severe overdose of digoxin? (A) Digoxin antibodies (B) Lidocaine infusion (C) Magnesium infusion (D) Phenytoin by mouth (E) Potassium by mouth
A The drug of choice in severe, massive overdose with any cardiac glycoside is digoxin antibody, Digibind. The other drugs listed are used in moderate overdosage associated with increased automaticity.
Which one of the following drugs is associated with clinically useful or physiologically important positive inotropic effect? (A) Captopril (B) Dobutamine (C) Enalapril (D) Losartan (E) Nesiritide
B Although they are extremely useful in heart failure, ACE inhibitors (eg, captopril, enalapril), and angiotensin receptor blockers (ARBs, eg, losartan) have no positive inotropic effect on the heart. Nesiritide is a vasodilator with diuretic effects and renal toxicity. Dobutamine is a β1-selective adrenoceptor agonist.
Which of the following drugs is the most effective in the emergency management of malignant hyperthermia? (A) Atropine (B) Dantrolene (C) Haloperidol (D) Succinylcholine (E) Vecuronium
B Prompt treatment is essential in malignant hyperthermia to control body temperature, correct acidosis, and prevent calcium release. Dantrolene interacts with the RyR1 channel to block the release of activator calcium from the sarcoplasmic reticulum, which prevents the tension-generating interaction of actin with myosin.
After your patient has been receiving digoxin for 3 wk, he presents to the emergency department with an arrhythmia. Which one of the following is most likely to contribute to the arrhythmogenic effect of digoxin? (A) Increased parasympathetic discharge (B) Increased intracellular calcium (C) Decreased sympathetic discharge (D) Decreased intracellular ATP (E) Increased extracellular potassium
B The effects of digitalis include increased vagal action on the heart (not arrhythmogenic) and increased intracellular calcium, including calcium overload, the most important cause of toxicity. Decreased sympathetic discharge and increased extracellular potassium and magnesium reduce digitalis arrhythmogenesis.
A patient with liver dysfunction is scheduled for a surgical procedure. Lorazepam or oxazepam can be used for preanesthetic sedation in this patient without special concern regarding excessive CNS depression because these drugs are (A) Actively secreted in the renal proximal tubule (B) Conjugated extrahepatically (C) Eliminated via the lungs (D) Reversible by administration of naloxone (E) Selective anxiolytics like buspirone
B The elimination of most benzodiazepines involves their metabolism by liver enzymes, including cytochrome P450 isozymes. In a patient with liver dysfunction, lorazepam and oxazepam, which are metabolized extrahepatically, are less likely to cause excessive CNS depression. Benzodiazepines are not eliminated via the kidneys or lungs. Flumazenil is used to reverse excessive CNS depression caused by benzodiazepines.
When working in outlying areas, this 62-year-old rancher is away from his house for 12-14 h at a time. He has an arrhythmia that requires chronic therapy. Which of the following has the longest half-life of all antiarrhythmic drugs? (A) Adenosine (B) Amiodarone (C) Disopyramide (D) Esmolol (E) Flecainide (F) Lidocaine (G) Mexiletine (H) Procainamide (I) Quinidine (J) Verapamil
B Amiodarone has the longest half-life of all the antiarrhythmics (weeks).
Which row in the following table correctly shows the major effects of full therapeutic doses of digoxin on the AV node and the ECG? AV Refractory Period QT Interval T Wave (A) Increased Increased Upright (B) Increased Decreased Inverted (C) Decreased Increased Upright (D) Decreased Decreased Upright (E) Decreased Increased Inverted
B Digitalis increases the AV node refractory period—a parasympathomimetic action. Its effects on the ventricles include shortened action potential and QT interval, and a change in repolarization with flattening or inversion of the T wave.
The clinical use of succinylcholine, especially in patients with diabetes, is associated with (A) Antagonism by pyridostigmine during the early phase of blockade (B) Aspiration of gastric contents (C) Decreased intragastric pressure (D) Histamine release in a genetically determined population (E) Metabolism at the neuromuscular junction by acetylcholinesterase
B Fasciculations associated with succinylcholine may increase intragastric pressure with possible complications of regurgitation and aspiration of gastric contents. The complication is more likely in patients with delayed gastric emptying such as those with esophageal dysfunction or diabetes. Histamine release resulting from succinylcholine is not genetically determined.
In deciding on a treatment regimen with procainamide for this patient, which of the following statements is most correct? (A) A possible drug interaction with digoxin suggests that digoxin blood levels should be obtained before and after starting procainamide (B) Hyperkalemia should be avoided to reduce the likelihood of procainamide toxicity (C) Procainamide cannot be used if the patient has asthma because it has a β-blocking effect (D) Procainamide cannot be used if the patient has angina because it has a β-agonist effect (E) Procainamide is not active by the oral route
B Hyperkalemia facilitates procainamide toxicity. Procainamide is active by the oral route and has a duration of action of 2-4 h (in the prompt-release form). Procainamide has no significant documented interaction with digoxin and no significant β-agonist or β-blocking action.
Which statement concerning the barbiturates is accurate? (A) Abstinence syndromes are more severe during withdrawal from phenobarbital than from secobarbital (B) Alkalinization of the urine accelerates the elimination of phenobarbital (C) Barbiturates may increase the half-lives of drugs metabolized by the liver (D) Compared with barbiturates, the benzodiazepines exhibit a steeper dose-response relationship (E) Respiratory depression caused by barbiturate overdosage can be reversed by flumazenil
B Withdrawal symptoms from use of the shorter-acting barbiturate secobarbital are more severe than with phenobarbital. The dose-response curve for benzodiazepines is flatter than that for barbiturates. Induction of liver drug-metabolizing enzymes occurs with barbiturates and may lead to decreases in half-life of other drugs. Flumazenil is an antagonist at BZ receptors and is used to reverse CNS depressant effects of benzodiazepines. As a weak acid (pKa 7), phenobarbital will be more ionized (nonprotonated) in the urine at alkaline pH and less reabsorbed in the renal tubule.
A 55-year-old man is admitted to the emergency department and is found to have an abnormal ECG. Overdose of an antiarrhythmic drug is considered. Which of the following drugs is correctly paired with its ECG effects? (A) Quinidine: Increased PR and decreased QT intervals (B) Flecainide: Increased PR, QRS, and QT intervals (C) Verapamil: Increased PR interval (D) Lidocaine: Decreased QRS and PR interval (E) Metoprolol: Increased QRS duration
C All the associations listed are incorrect except verapamil Because calcium blockers slow AV conduction, group 4 drugs such as verapamil and diltiazem increase PR interval and have little effect on the other ECG variables.
Which of the following best describes the mechanism of action of benzodiazepines? (A) Activate GABAB receptors in the spinal cord (B) Block glutamate receptors in hierarchical neuronal pathways in the brain (C) Increase frequency of opening of chloride ion channels coupled to GABAA receptors (D) Inhibit GABA transaminase to increase brain levels of GABA (E) Stimulate release of GABA from nerve endings in the brain
C Benzodiazepines exert most of their CNS effects by increasing the inhibitory effects of GABA, interacting with components of the GABAA receptor-chloride ion channel macromolecular complex to increase the frequency of chloride ion channel opening. Benzodiazepines do not affect GABA metabolism or release, and they are not GABA receptor agonists because they do not interact directly with the binding site for GABA.
A 36-year-old woman with a history of poorly controlled thyrotoxicosis has recurrent episodes of tachycardia with severe shortness of breath. When she is admitted to the emergency department with one of these episodes, which of the following drugs would be most suitable? (A) Amiodarone (B) Disopyramide (C) Esmolol (D) Quinidine (E) Verapamil
C Beta blockers are the most effective agents in acute thyrotoxic arrhythmias. Esmolol is a parenteral, rapid-acting β blocker
It is possible that this patient will have to increase the dose of the analgesic as his condition progresses as a result of developing tolerance. However, tolerance will not develop to a significant extent with respect to (A) Biliary smooth muscle (B) Emesis (C) Pupillary constriction (D) Sedation (E) Urinary retention
C Chronic use of strong opioid analgesics leads to the development of tolerance to their analgesic, euphoric, and sedative actions. Tolerance also develops to their emetic effects and to effects on some smooth muscle, including the biliary and the urethral sphincter muscles. However, tolerance does not develop significantly to the constipating effects or the miotic actions of the opioid analgesics.
Which drug has spasmolytic activity and could also be used in the management of seizures caused by overdose of a local anesthetic? (A) Baclofen (B) Cyclobenzaprine (C) Diazepam (D) Gabapentin (E) Tizanidine
C Diazepam is both an effective antiseizure drug and a spasmolytic. The spasmolytic action of diazepam is thought to be exerted partly in the spinal cord because it reduces spasm of skeletal muscle in patients with cord transection. Cyclobenzaprine is used for acute local spasm and has no antiseizure activity.
Which of the following drugs slows conduction through the AV node and has its primary action directly on L-type calcium channels? (A) Adenosine (B) Amiodarone (C) Diltiazem (D) Esmolol (E) Flecainide (F) Lidocaine (G) Mexiletine (H) Procainamide (I) Quinidine
C Diltiazem is the calcium channel blocker in this list. (Beta blockers also slow AV conduction but have much smaller effects on calcium channels.)
A 63-year-old man is undergoing radiation treatment as an outpatient for metastatic bone cancer. His pain has been treated with a fixed combination of oxycodone plus acetaminophen taken orally. Despite increasing doses of the analgesic combination, the pain is getting worse. The most appropriate oral medication for his increasing pain is (A) Buprenorphine (B) Codeine plus aspirin (C) Hydromorphone (D) Pentazocine (E) Tramadol
C In most situations, pain associated with metastatic carcinoma ultimately necessitates the use of an opioid analgesic that is equivalent in strength to morphine, so hydromorphone, oxymorphone, or levorphanol would be indicated. Pentazocine or the combination of codeine plus salicylate would not be as effective as the original drug combination. Propoxyphene is even less active than codeine alone. Buprenorphine, a mixed agonist-antagonist, is not usually recommended for cancerassociated pain because it has a limited maximum analgesic effect ("ceiling") and because of possible dysphoric and psychotomimetic effects.
A 60-year-old man comes to the emergency department with severe chest pain. ECG reveals ventricular tachycardia with occasional normal sinus beats, and ST-segment changes suggestive of ischemia. A diagnosis of myocardial infarction is made, and the man is admitted to the cardiac intensive care unit. His arrhythmia should be treated immediately with (A) Adenosine (B) Digoxin (C) Lidocaine (D) Quinidine (E) Verapamil
C Lidocaine has limited applications as an antiarrhythmic drug, but emergency treatment of myocardial infarction arrhythmias is one of the most important. Lidocaine is also useful in digoxin-induced arrhythmias. After recovery from the acute phase of a myocardial infarction, β blockers are used for 2 yr or more to prevent sudden death arrhythmias.
A muscarinic receptor antagonist would probably not be needed for reversal of the skeletal muscle relaxant actions of a nondepolarizing drug if the agent used was (A) Cisatracurium (B) Mivacurium (C) Pancuronium (D) Tubocurarine (E) Vecuronium
C One of the distinctive characteristics of pancuronium is that it can block muscarinic receptors, especially those in the heart. It has sometimes caused tachycardia and hypertension and may cause dysrhythmias in predisposed individuals.
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
C 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 dedetoxification and maintenance programs.
This drug used in the management of insomnia facilitates the inhibitory actions of GABA, but it lacks anticonvulsant or muscle-relaxing properties and has minimal effect on sleep architecture. Its actions are antagonized by flumazenil. (A) Buspirone (B) Chlordiazepoxide (C) Eszopiclone (D) Ramelteon (E) Phenobarbital
C Only two of the drugs listed are used for insomnia, eszopiclone and ramelteon. Eszopiclone, zaleplon, and zolpidem are related hypnotics that, though structurally different from benzodiazepines, appear to have a similar mechanism of action. However, unlike benzodiazepines, these drugs are not used in seizures or in muscle spasticity states. Compared with benzodiazepines, the newer hypnotics are less likely to alter sleep patterns. Ramelteon activates melatonin receptors in the suprachiasmatic nuclei. Buspirone is not a hypnotic!
Which drug will be most effective in alleviating the symptoms experienced by this patient? (A) Buprenorphine (B) Codeine (C) Methadone (D) Naltrexone (E) Tramadol
C 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.
A 45-year-old woman with hyperlipidemia and frequent migraine headaches develops angina of effort. Which of the following is relatively contraindicated because of her migraines? (A) Amlodipine (B) Diltiazem (C) Metoprolol (D) Nitroglycerin (E) Verapamil
D Acute migraine headache is associated with vasodilation of meningeal arteries. Of the drugs listed, only nitroglycerin is commonly associated with headache. In fact, calcium channel blockers and β blockers have been used with some success as prophylaxis for migraine.
A new 60-year-old patient presents to the medical clinic with hypertension and angina. He is 1.8 meters tall with a waist measurement of 1.1 m. Weight is 97 kg. Blood pressure is 150/95 and pulse 85. In considering adverse effects of possible drugs for these conditions, you note that an adverse effect that nitroglycerin and prazosin have in common is (A) Bradycardia (B) Impaired sexual function (C) Lupus erythematosus syndrome (D) Orthostatic hypotension (E) Weight gain
D Both drugs cause venodilation and reduce venous return sufficiently to cause some degree of postural hypotension. Bradycardia, lupus, weight gain, and urinary retention occur with neither of them, but prazosin has been used to relieve urinary retention in men with prostatic hyperplasia.
The most likely explanation for the increased sensitivity of elderly patients after a single dose of a benzodiazepine is (A) Age-dependent changes in brain function (B) Decreases in plasma protein binding (C) Decreased metabolism of lipid-soluble drugs (D) Decreases in renal function (E) Increased cerebral blood flow
D Clonazepam and phenobarbital are both used in seizure disorders. Chronic administration of phenobarbital (but not clonazepam) increases the activity of hepatic drug-metabolizing enzymes, including several cytochrome P450 isozymes. This can increase the rate of metabolism of drugs administered concomitantly, resulting in decreases in the intensity and duration of their effects.
Which drug used in the maintenance treatment of patients with tonic-clonic or partial seizure states increases the hepatic metabolism of many drugs including both phenytoin and warfarin? (A) Buspirone (B) Clonazepam (C) Eszopiclone (D) Phenobarbital (E) Triazolam
D Clonazepam and phenobarbital are both used in seizure disorders. Chronic administration of phenobarbital (but not clonazepam) increases the activity of hepatic drug-metabolizing enzymes, including several cytochrome P450 isozymes. This can increase the rate of metabolism of drugs administered concomitantly, resulting in decreases in the intensity and duration of their effects.
You are on your way to take an examination and you suddenly get an attack of diarrhea. If you stop at a nearby drugstore for an over-the-counter opioid with antidiarrheal action, you will be asking for (A) Codeine (B) Dextromethorphan (C) Diphenoxylate (D) Loperamide (E) Nalbuphine
D Codeine and nalbuphine could decrease gastrointestinal peristalsis, but not without marked side effects (and a prescription). Dextromethorphan is a cough suppressant. The other 2 drugs listed are opioids with antidiarrheal actions. Diphenoxylate is not available over the counter because it is a constituent of a proprietary combination that includes atropine sulfate (Lomotil).
Which of the following is the best-documented mechanism of beneficial action of cardiac glycosides? (A) A decrease in calcium uptake by the sarcoplasmic reticulum (B) An increase in ATP synthesis (C) A modification of the actin molecule (D) An increase in systolic cytoplasmic calcium levels (E) A block of cardiac β adrenoceptors
D Digitalis does not decrease calcium uptake by the sarcoplasmic reticulum or increase ATP synthesis; it does not modify actin. Cardiac adrenoceptors are not affected. The most accurate description of digitalis's mechanism in this list is that it increases systolic cytoplasmic calcium indirectly by inhibiting Na+ /K+ ATPase and altering Na/Ca exchange.
An 82-year-old woman, otherwise healthy for her age, has difficulty sleeping. Triazolam is prescribed for her at one half of the conventional adult dose. Which statement about the use of triazolam in this elderly patient is accurate? (A) Ambulatory dysfunction is unlikely to occur in elderly patients taking one half of the conventional adult dose (B) Hypertension is a common adverse effect of benzodiazepines in elderly patients (C) Over-the-counter cold medications may antagonize the hypnotic effects of the drug (D) The patient may experience amnesia, especially if she also consumes alcoholic beverages (E) Triazolam does not cause rebound insomnia on abrupt discontinuance
D In elderly patients taking benzodiazepines, hypotension is far more likely than an increase in blood pressure. Elderly patients are more prone to the CNS depressant effects of hypnotics; a dose reduction of 50% may still cause excessive sedation with possible ambulatory impairment. Additive CNS depression occurs commonly with drugs used in overthe-counter cold medications, and rebound insomnia can occur with abrupt discontinuance of benzodiazepines used as sleeping pills. Alcohol enhances psychomotor depression and the amnestic effects of the benzodiazepines.
A 57-year-old man is admitted to the emergency department with chest pain and a fast irregular heart rhythm. The ECG shows an inferior myocardial infarction and ventricular tachycardia. Lidocaine is ordered. When used as an antiarrhythmic drug, lidocaine typically (A) Increases action potential duration (B) Increases contractility (C) Increases PR interval (D) Reduces abnormal automaticity (E) Reduces resting potential
D Lidocaine reduces automaticity in the ventricles; the drug does not alter resting potential or AP duration and does not increase contractility.
Which of the following is a common direct or reflex effect of nitroglycerin? (A) Decreased heart rate (B) Decreased venous capacitance (C) Increased afterload (D) Increased cardiac force (E) Increased diastolic myocardial fiber tension
D Nitroglycerin increases heart rate and venous capacitance and decreases afterload and diastolic fiber tension. It increases cardiac contractile force because the decrease in blood pressure evokes a compensatory increase in sympathetic discharge.
Which drug is most likely to cause hyperkalemia leading to cardiac arrest in patients with spinal cord injuries? (A) Baclofen (B) Dantrolene (C) Pancuronium (D) Succinylcholine (E) Vecuronium
D Skeletal muscle depolarization by succinylcholine releases potassium from the cells, and the ensuing hyperkalemia can be life-threatening in terms of cardiac arrest. Patients most susceptible include those with extensive burns, spinal cord injuries, neurologic dysfunction, or intra-abdominal infection.
When nitrates are used in combination with other drugs for the treatment of angina, which one of the following combinations results in additive effects on the variable specified? (A) Beta blockers and nitrates on end-diastolic cardiac size (B) Beta blockers and nitrates on heart rate (C) Beta blockers and nitrates on venous tone (D) Calcium channel blockers and β blockers on cardiac force (E) Calcium channel blockers and nitrates on heart rate
D The effects of β blockers (or calcium channel blockers) and nitrates on heart size, force, venous tone, and heart rate are opposite. The effects of β blockers and calcium channel blockers on the variables specified here are the same.
In advising the patient about the adverse effects he may notice, you point out that nitroglycerin in moderate doses often produces certain symptoms. Which of the following effects might occur due to the mechanism listed? (A) Constipation (B) Dizziness due to reduced cardiac force of contraction (C) Diuresis due to sympathetic discharge (D) Headache due to meningeal vasodilation (E) Hypertension due to reflex tachycardia
D The nitrates relax many types of smooth muscle, but the effect on motility in the colon is insignificant. Nitroglycerin causes hypotension as a result of arterial and venous dilation. Dilation of arteries in the meninges has no effect on central nervous system function but does cause headache
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
D 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.
A patient who has been taking digoxin for several years for atrial fibrillation and chronic heart failure is about to receive atropine for another condition. A common effect of digoxin (at therapeutic blood levels) that can be almost entirely blocked by atropine is (A) Decreased appetite (B) Headaches (C) Increased atrial contractility (D) Increased PR interval on ECG (E) Tachycardia
D The parasympathomimetic effects of digitalis can be blocked by muscarinic blockers such as atropine. The only parasympathomimetic effect in the list provided is increased PR interval, a manifestation of slowed AV conduction.
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"
D 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.
Which drug (related to clonidine) is most often associated with hypotension? (A) Baclofen (B) Pancuronium (C) Succinylcholine (D) Tizanidine (E) Vecuronium
D Tizanidine causes hypotension via α2-adrenoceptor activation, like its congener clonidine. Hypotension may occur with tubocurarine (not listed) due partly to histamine release and to ganglionic blockade.
A 24-year-old stockbroker has developed a "nervous disposition." He is easily startled, worries about inconsequential matters, and sometimes complains of stomach cramps. At night he grinds his teeth in his sleep. There is no history of drug abuse. Diagnosed as suffering from generalized anxiety disorder, he is prescribed buspirone. The patient should be informed to anticipate (A) A need to continually increase drug dosage because of tolerance (B) A significant effect of the drug on memory (C) Additive CNS depression with alcoholic beverages (D) That the drug is likely to take a week or more to begin working (E) That if he stops taking the drug abruptly, he will experience withdrawal signs
D Buspirone is a selective anxiolytic with pharmacologic characteristics different from those of sedative-hypnotics. Buspirone has minimal effects on cognition or memory; it is not additive with ethanol in terms of CNS depression; tolerance is minimal; and it has no dependence liability. Buspirone is not effective in acute anxiety because it has a slow onset of action.
A 43-year-old very overweight man complains of not sleeping well and feeling tired during the day. He says that his wife is the cause of the problem because she wakes him up several times during the night because of his loud snores. This appears to be a breathing-related sleep disorder, so you should probably write a prescription for (A) Clorazepate (B) Diazepam (C) Flurazepam (D) Pentobarbital (E) None of the above
E Benzodiazepines and barbiturates are contraindicated in breathing-related sleep disorders because they further compromise ventilation. In obstructive sleep apnea (pickwickian syndrome), obesity is a major risk factor. The best prescription you can give this patient is to lose weight.
Characteristics of phase I depolarizing neuromuscular blockade due to succinylcholine include (A) Easy reversibility with nicotinic receptor antagonists (B) Marked muscarinic blockade (C) Muscle fasciculations only in the later stages of block (D) Reversibility by acetylcholinesterase (AChE) inhibitors (E) Sustained tension during a period of tetanic stimulation
E Phase I depolarizing blockade caused by succinylcholine is not associated with antagonism at muscarinic receptors, nor is it reversible with cholinesterase inhibitors. Muscle fasciculations occur at the start of the action of succinylcholine.
One year later, the patient returns complaining that his nitroglycerin works well when he takes it for an acute attack but that he is now having more frequent attacks and would like something to prevent them. Useful drugs for the prophylaxis of angina of effort include (A) Amyl nitrite (B) Esmolol (C) Sublingual isosorbide dinitrate (D) Sublingual nitroglycerin (E) Verapamil
E The calcium channel blockers and the β blockers are generally effective in reducing the number of attacks of angina of effort, and most have durations of 4-8 h. Oral and transdermal nitrates have similar or longer durations. Amyl nitrite and the sublingual nitrates have short durations of action (a few minutes to 30 min). Esmolol (an intravenous β blocker) must be given intravenously and also has a very short duration of action. These drugs are of no value in prophylaxis.
If this patient should take an overdose and manifest severe acute procainamide toxicity with markedly prolonged QRS, which of the following should be given immediately? (A) A calcium chelator such as EDTA (B) Digitalis (C) Nitroprusside (D) Potassium chloride (E) Sodium lactate
E The most effective therapy for procainamide toxicity appears to be concentrated sodium lactate. This drug may (1) increase sodium current by increasing the sodium ion gradient and (2) reduce drug-receptor binding by alkalinizing the tissue.
Another patient is admitted to the emergency department after a drug overdose. He is noted to have hypotension and severe bradycardia. He has been receiving therapy for hypertension and angina. Which of the following drugs in high doses causes bradycardia? (A) Amlodipine (B) Isosorbide dinitrate (C) Nitroglycerin (D) Prazosin (E) Verapamil
E Isosorbide dinitrate (like all the nitrates) and prazosin can cause reflex tachycardia. Amlodipine, a dihydropyridine calcium channel blocker, causes much more vasodilation than cardiac depression and may also cause reflex tachycardia. Verapamil typically slows heart rate and high doses may cause severe bradycardia.
Which statement about nalbuphine is accurate? (A) Activates µ receptors (B) Does not cause respiratory depression (C) Is a nonsedating opioid (D) Pain-relieving action is not superior to that of codeine (E) Response to naloxone in overdose may be unreliable
E Nalbuphine and butorphanol are κ agonists, with weak µ-receptor antagonist activity. They have analgesic efficacy superior to that of codeine, but it is not equivalent to that of strong opioid receptor agonists. Although these mixed agonist-antagonist drugs are less likely to cause respiratory depression than strong µ activators, if depression does occur, reversal with opioid antagonists such as naloxone is unpredictable. Sedation is common.
Certain drugs can cause severe hypotension when combined with nitrates. Which of the following interacts with nitroglycerin by inhibiting the metabolism of cGMP? (A) Atenolol (B) Hydralazine (C) Isosorbide mononitrate (D) Nifedipine (E) Ranolazine (F) Sildenafil (G) Terbutaline
F Sildenafil inhibits phosphodiesterase 5, an enzyme that inactivates cGMP. The nitrates (via nitric oxide) increase the synthesis of cGMP. This combination is synergistic.
