Pharmacology Module 1

A patient with Parkinson's disease who takes levodopa/carbidopa (Sinemet) comes to the clinic for a semiannual physical examination. Which question is the most important for the nurse to ask?

"Are you having vivid dreams or visual hallucinations?"

Someone asks a nurse about a new drug that is in preclinical testing and wants to know why it cannot be used to treat a friend's illness. Which statement by the nurse is correct?

"At this stage of drug development, the safety and usefulness of the medication is unknown."

A patient taking oral contraceptives thinks she may be pregnant. As part of this patient's history, what will the nurse ask the patient?

"Do you take seizure medication?"

A patient will begin using a transdermal preparation of a muscarinic antagonist for overactive bladder (OAB). The nurse teaches the patient what to do if side effects occur. Which statement by the patient indicates the need for further teaching?

"I will take Benadryl for any itching caused by a local reaction to the patch."

A client with a seizure disorder is prescribed the anticonvulsant phenytoin (dilantin). Which statement indicates the client understand the medication teaching?

"I will use a soft bristled toothbrush to brush my teeth." The client should do this to prevent gum irritation and bleeding b/c overgrowth of gums is a side effect of this medication.

The family member of a client diagnosed with early-stage AD who was prescribed the cholinesterase inhibitor donepezil (Aricept) w/o improvement asks the nurse, "can anything be done to slow the disease since this med does not work?"

"Your loved one may respond to a different med of the same type."

The female client diagnosed with epilepsy tells the nurse "I am very scared to get pregnant since I am taking medication for my epilepsy." Which statement is the nurse's best response?

"Many women with epilepsy give birth to normal infants." - epilepsy medication does have teratogenic properties but many women still can give birth to normal infants.

A postoperative patient is being discharged home with acetaminophen/hydrocodone (Lortab) for pain. The patient asks the nurse about using Tylenol for fever. Which statement by the nurse is correct?

"Taking the two medications together poses a risk of drug toxicity."

Which statement made by the wife of a client diagnosed with PD indicates that teaching about the med regimen has been effective?

"The medications provide symptom management, but the effects may not last."

The nurse is preparing to administer penicillin G intramuscularly to a child. The child's parents ask why the drug cannot be given in an oral liquid form. What is the nurse's reply?

"This drug would be inactivated by enzymes in the stomach."

A patient with Parkinson's disease who has been positively responding to drug treatment with levodopa/carbidopa (Sinemet) suddenly develops a relapse of symptoms. Which explanation by the nurse is appropriate?

"This is called the 'on-off' phenomenon. Your healthcare provider can change your medication regimen to help diminish this effect."

The client with a seizure disorder who is taking carbamazepine (Tegretol) tells the clinic nurse, "I am taking evening primrose oil for my premenstrual cramps and it is really working." Which statement would be the nurse's best response?

"You should inform your healthcare provider about taking this herb." Evening primrose oil may lower the seizure threshold and the Tegretol dose may need to be modified.

Direct chemical interactions occur most commonly when drugs are

combined in IV solutions

Activation of alpha1 receptors activates 2 responses that can be of therapeutic use:

1. vasoconstriction (used most often for this) 2. mydriasis (almost never used for this)

Muscarinic overdose symptoms

1. Blurred vision 2. Profuse salivation 3. hypotension 4. bradycardia 5. bronchospasm 6. diarrhea 7. lacrimation

Disadvantages of IV injection (6)

1. Irreversible 2. Expensive 3. Inconvenient 4. Difficult to do 5. Risk of fluid overload, infection, & embolism 6. Drug must be water soluble

Steps to minimize drug-drug interactions

1. Reduce # of drugs 2. take thorough drug history 3. be aware of possible illicit drug use 4. adjust dosages 5. adjust timing 6. monitor for signs of toxicity 7. be vigilant when pt is taking drug w/low therapeutic index

By activating central alpha2 receptors we can produce two useful effects:

1. Reduction of sympathetic outflow to the heart and blood vessels 2. relief of severe pain

Advantages of PO administration

1. Relatively inexpensive 2. Patient can do it 3. Easy 4. potentially reversible 5. Convenient

Six rights of medication administration

1. Right drug 2. Right patient 3. Right dose 4. Right time 5. Right route 6. Right documentation

3 Most important properties of drugs

1. Selectivity 2. Safety 3. Effectiveness

2 Pathologic conditions that affect blood flow:

1. abscesses (avascular pus pocket) 2. Tumors - low blood flow in core

Drug distribution is determined by 3 factors:

1. blood flow to tissues 2. ability of drug to exit vascular system 3. Ability of drug to enter cells

Drugs can interact thru 4 basic mechanisms:

1. direct chemical or physical interaction 2. Pharmacokinetic processes 3. Pharmacodynamic processes 4. Combined toxicity

Anaphylactic Shock is a manifestation of a ____. The reaction is characterized by ___, ___, and ____.

1. edema of the glottis 2. bronchoconstriction 3. hypotension

5 Drugs capable of activating alpha1 receptors:

1. epinephrine 2. NE 3. Phenylephrine 4. ephedrine 5. dopamine

3 Adverse effects of alpha1 activation:

1. hypertension 2. necrosis (when injected IM) 3. bradycardia

Adverse effects of beta2 activation

1. hypoglycemia (in pts w/diabetes) 2. Tremors

Disadvantages to PO administration

1. variability 2. inactivation of some drugs by gastric acid and digestive enzymes 3. possible nausea 4. patient must be conscious

The nurse is caring for several patients. For which patient is propranolol (Inderal) most likely to be contraindicated?

A 60-year-old woman with diabetes, because Propranolol inhibits glycogenolysis and thus can produce hypoglycemia, which can cause problems in patients with diabetes. It also suppresses tachycardia, which is an important warning sign of hypoglycemia in diabetic patients. It is safe to use propranolol in dysrhythmias, hypertension, and angina.

Dose loading vs maintenance dose:

A loading dose is administered in order to achieve plateau quickly with a drug. After high drug level is achieved, a plateau is maintained by administering smaller doses. The smaller doses are referred to as maintenance doses.

Which statement is the scientific rationale for prescribing and administering donepezil (Aricept), a cholinesterase inhibitor?

Aricept increases the availability of acetylcholine at cholinergic synapses.

Best way to reduce toxicity of IV administration to CNS

Administer slowly - over span of 1 minute

ADR

Adverse drug reaction - any noxious unintended, and undesired effect that occurs @normal drug doses

The client diagnosed with AD is prescribed rivastigmine (Exelon), a cholinesterase inhibitor. Which med should the nurse question administering to the client?

Amitriptyline (Elavil), a tricyclic antidepressant. Tricyclic antidepressants, antihistamines, and antipsychotics can reduce the client's response to cholinesterase inhibitors.

Sentinel Event

An unexpected occurrence involving death or serious injury

A patient is receiving dobutamine (Dobutrex) as a continuous infusion in the immediate postoperative period. The patient also is receiving a diuretic. What adverse drug reactions are possible in this patient? (Select all that apply.)

Angina, Dysrhythmias, Tachycardia

Pre-anesthetic medications-use of anticholinergics

Anticholinergic drugs (eg, atropine) may be given to decrease the risk of bradycardia during surgery. Surgical manipulations can trigger parasympathetic reflexes, which in turn can produce profound vagal slowing of the heart. Pretreatment with a cholinergic antagonist prevents bradycardia from this cause.

Anticholinergic Prototype Drug

Atropine: Blocks muscarinic receptors- shuts down the parasympathetic system. Used for cardiac benefits during surgery to help counteract heart depression by anethesia. Helps with bradycardia, helps alleviate fast GI motility (diarrhea, dysentery), cholingeric overdose. Can be used for peptic ulcers and asthma but no. Adverse effects: (Classic) Dry mouth (block salivary glands), blurred vision/photophbia (dilated eyes cannot adapt to brightness), elevated Intraocular pressure, urinary rentention, constipation, anhidrosis (no sweating), tachycardia, asthma (thickening and drying of secretions)

Cholinergic Prototype Drug

Bethanechol (for urinary retention) mechanism: reversibly binds to muscarinic cholinergic receptors to cause activation. Adverse effects: hypotension, bradycardia, secretions of GI, cramps, diarrhea, bronchoconstriction. Contraindicated: asthma patients, low blood pressure, low cardiac output, gastric ulcers, intestinal or urinary obstruction, weakness of bladder wall, hyperthyroid.

Bethanechol-side effects:

Bethanechol is a muscarinic agonist. It is approved only to treat urinary retention. It can cause hypotension and bradycardia. Bethanechol can also cause diarrhea, excessive salivation, abdominal cramps. It also increases pressure in the urinary tract and should not be given to patients with an obstruction or weak bladder wall. Causes bronchoconstriction. Bethanechol is contraindicated for patients with hyperthryoid because it can cause dysrhythmia.

Which statement should the nurse include in the teaching plan for a patient being started on levodopa/carbidopa (Sinemet) for newly diagnosed Parkinson's disease?

Change positions slowly because it can cause postural hypotension early on in treatment.

Which statement is an advantage of administering the catechol-O-methyltransferase (COMT) inhibitor entacapone (Comtan) to a client diagnosed with PD?

Comtan causes blood levels of levodopa to be smoother and more sustained.

A postoperative patient reports pain, which the patient rates as an 8 on a scale from 1 to 10 (10 being the most extreme pain). The prescriber has ordered acetaminophen (Tylenol) 650 mg PO every 6 hours PRN pain. What will the nurse do?

Contact the provider to request a different analgesic medication.

The client diagnosed with early-stage PD has been prescribed pramipexole (Mirapex), a dopamine agonist med. Which side effect of this med should the nurse teach the client?

Daytime somnolence. This is seen in about 22% of clients taking Mirapex. A few clients experience an overwhelming and irresistible sleepiness that comes on w/o warning.

The nurse is caring for a client newly diagnosed with PD who is receiving the anti-PD med levodopa. Which interventions should the nurse implement?

Instruct the client to rise slowly from a seated or lying position (can cause postural hypotension), teach about on-off effects, tell the client that the sweat and urine my become darker.

The client with a seizure disorder is prescribed the anticonvulsant fosphenytoin (cerebyx). Which interventions should the nurse discuss with the client?

Instruct the client to wear a MedicAlert bracelet and carry ID, tell the client to not self-medicate with over-the-counter meds, and explain the importance of maintaining adequate nutritional intake.

All barriers to absorption are bypassed with ____ administration

IV

The client diagnosed with PD is prescribed the antiviral drug amantadine (Symmetrel). Which info should the nurse teach the client?

If symptoms return, the client should notify the HCP. This is b/c the effectiveness of amantadine may diminish in 3-6 mos.

Dopamine is administered to a patient who has been experiencing hypotensive episodes. Other than an increase in blood pressure, which indicator would the nurse use to evaluate a successful response?

Increase in urine output

The client newly diagnosed with a seizure disorder also has Type 2 diabetes. The health-care provider prescribes phenytoin (Dilantin) for the client. Which intervention should the nurse implement?

Instruct the client to monitor his or her blood glucose more closely. Phenytoin may inhibit insulin release, thus causing an increase in glucose level.

Which data should the nurse assess for the client with a seizure disorder who is taking valproate (Depakote)?

Liver enzymes b/c hepatotoxicity is a possible ADR with this medication.

A prescriber has ordered pilocarpine (Pilocar). A nurse understands that the drug stimulates muscarinic receptors and would expect the drug to have which action?

Lower intraocular pressure in patients with glaucoma

The nurse is completing an admission assessment on a client being admitted to a medical unit diagnosed with pneumonia. The client's list of home meds includes Ladix, a loop diuretic; Metamucil, a bulk laxative; and Reminyl, a cholinesterase inhibitor. Which intervention should the nurse implement first?

Make sure the client has a room near the nursing station. Reminyl is prescribed for mild to moderate AD, and the safety of the client should be the nurse's first concern. Moving the client to a room that can be observed more closely is one of the first steps in a falls prevention protocol.

Factors that can alter physiologic response to drug

Multiple factors can increase the patient's risk of adverse reactions to a particular drug. Impaired liver and kidney function, age, body composition, pregnancy, diet, genetic heritage, other drugs being used, and practically any physiologic condition.

Levodopa-adverse effects:

Nausea and vomiting, Dyskinesia's, Postural hypotension (reduced by taking salt & H2O), Psychosis (hallucinations, vivid dreams) & darken sweat & urine.

The nurse caring for clients on a med psychiatric unit has received the morning shift report. To whom should the nurse administer meds first?

The client diagnosed with AD who is angry and isoriented and has an antipsychotic PRN. This pt could harm himself or others.

Post-anesthetic medications for pain & nausea

Patients recovering from anesthesia often experience nausea and vomiting. This can be suppressed with antiemetics. Among the most effective is ondansetron [Zofran], a drug developed to suppress nausea and vomiting in patients undergoing cancer chemotherapy. Other commonly used antiemetics are promethazine and droperidol.

The nurse is teaching a patient about taking warfarin and asks if the patient takes aspirin. This assessment by the nurse reflects a knowledge of which type of drug interaction?

Potentiative effects

Why does the nurse anticipate administering metoprolol (Lopressor) rather than propranolol (Inderal) for diabetic patients who need a beta-blocking agent?

Propranolol causes both beta1 and beta2 blockade and Metoprolol is beta1 selective and therefore can be used in patients with diabetes. Diabetics are especially dependent on beta2-mediated glycogenolysis as a way to overcome severe reductions in blood glucose levels (caused by overdosing with insulin).

The _____ is a measure of the time required for the ventricles to repolarize after each contraction. When the QT interval is prolonged, patients can develop a _____ known as torsades de pointes, which can progress to potentially fatal ventricular fibrillation.

QT interval; dysrhythmia

Which client diagnosed with PD should the nurse question administering the anticholinergic med benztropine (Cogentin)?

The client diagnosed with glaucoma. Anticholinergics block cholinergic receptors in the eye and may precipitate or aggravate glaucoma.

The elderly client diagnosed with PD has been prescribed carbidopa/levodopa (Sinemet). Which data indicates the medication has been effective?

The client is able to walk upright without stumbling.

Boxed warnings

The boxed warning, also known as a black box warning, is the strongest safety warning a drug can carry and still remain on the market. Text for the warning is presented inside a box with a heavy black border. The FDA requires a boxed warning for drugs it considers especially dangerous. The purpose of the warning is to alert prescribers to 1) potentially severe side effects (eg, life-threatening dysrhythmias, suicidality, major fetal harm) as well as 2) ways to prevent or reduce harm (eg, avoiding a teratogenic drug during pregnancy). The boxed warning should provide a concise summary of the adverse effects. They must also have a medication guide & prominently show the box on the package, label, and magazine ads.

Which statement indicates the scientific rationale for the combination drug carbidopa/levodopa (Sinemet) prescribed for PD?

The carbidopa delays the breakdown of the levodopa in the periphery so more dopamine get to the brain.

A patient is receiving intravenous gentamicin. A serum drug test reveals toxic levels. The dosing is correct, and this medication has been tolerated by this patient in the past. Which could be a probable cause of the test result?

The patient is taking another medication that binds to serum albumin.

The nurse is preparing a care plan for a client diagnosed with PD. Which statement is the goal of medication therapy for the client diagnosed with PD?

The client will maintain functional ability.

The client newly diagnosed with epilepsy is prescribed an anticonvuslant medication. Which information should the nurse tell the client?

The medication dosage will start low and gradually increase over a few weeks.

The client diagnosed with PD has been on long-term levodopa, and anti-PD drug. Which data supports the reason for placing the client on a "drug holiday"?

The therapeutic effects of the drug have diminished and the adverse effects have increased.

Therapeutic index:

The therapeutic index is a measure of a drug's safety. A large, or high, therapeutic index indicates that a drug is relatively safe. The therapeutic index is a ratio of the drugs LD (lethal dose) to the ED (effective dose).

What is the goal of pharmacologic therapy in the treatment of Parkinson's disease?

To balance cholinergic and dopaminergic activity in the brain

_____ is an adverse drug reaction caused by excessive dosing. Examples include coma from an overdose of morphine and severe hypoglycemia from an overdose of insulin. Although the formal definition of toxicity includes only those severe reactions that occur when dosage is excessive, in everyday parlance the term toxicity has come to mean any severe ADR, regardless of the dose that caused it.

Toxicity

The nurse in the cardiac care unit is caring for a patient receiving epinephrine. Which assessment criterion takes priority in the monitoring for adverse effects of this drug?

cardiac rhythm

The nurse is caring for a patient receiving propranolol (Inderal). Which finding is most indicative of an adverse effect of this drug?

Wheezing - this drug is a beta blocker and beta blockers can cause bronchoconstriction.

A psychiatric nurse is teaching a patient about an antidepressant medication. The nurse tells the patient that therapeutic effects may not occur for several weeks. The nurse understands that this is likely the result of:

changes in the brain as a result of prolonged drug exposure.

A nurse prepares to administer propranolol (Inderal) to a patient recovering from acute myocardial infarction. The patient's heart rate is 52 beats per minute, and the rhythm is regular. What action should the nurse take next?

Withhold the dose and notify the prescriber.

Alpha1

adranergic receptor located on eyes, arterioles, skin, viscera, veins, bladder, male sex organ

Beta1

adrenergic receptor located in heart and kidney

Alpha2

adrenergic receptor located on presynaptic nerve terminals

Beta 2

adrenergic receptors located on arterioles, heart, lungs, skeletal muscles, bronchi, uterus, liver

An ______ is an immune response. For an allergic reaction to occur, there must be prior sensitization of the immune system. Once the immune system has been sensitized to a drug, reexposure to that drug can trigger an allergic response. The intensity of allergic reactions can range from mild itching to severe rash to anaphylaxis.

allergic reaction

The nurse is preparing to give epinephrine by the IV push route. Which actions are essential before giving this drug?

assess the patency of the IV line, review the allergy history, assess the vital signs

Albuterol is used for treatment of _____

asthma

A nurse prepares to administer a new prescription for bethanechol (Urecholine). Which information in the patient's history should prompt the nurse to consult with the prescriber before giving the drug?

asthma - b/c bethanechol is a muscarinic agonist it can produce bronchospasms.

Asthma can be treated with

beta2 agonists

Practically all of the applications of propranolol are based on _________ in the heart. The most important indications are ______, _____,_____ and ______.

blockade of beta1 receptors; hypertension, angina pectoris, cardiac dysrhythmias, and myocardial infarction

Other adverse effects of propranolol (Inderal) include:

bradycardia, atrioventricular (AV) heart block, heart failure, rebound cardiac excitation, inhibition of glycogenolysis, and potential central nervous system (CNS) effects.

In Parkinson's disease there is an imbalance between _____ and _____ in the _____. The imbalance is a result of ______.

dopamine ACh striatum degeneration of the neurons that supply dopamine to the striatum

Two types of drugs are used to treat PD: _____ & ____. ____ is the preferred type.

dopaminergic and anticholinergic dopaminergic is preferred type

Iatrogenic Disease

drug induced disease

A patient asks why albuterol causes a feeling of jitteriness when it is used to treat wheezing. The nurse knows that albuterol is a beta-adrenergic agonist that acts on beta2 receptor sites to cause smooth muscle dilation in the bronchioles of the lungs, but that it also can sometimes act on beta1receptor sites in skeletal muscles to cause tremors. To explain this to the patient, the nurse will rely on knowledge of:

drug selectivity.

P450 System

enzymes in liver that aid in metabolism of drugs

____, injected ____ is the treatment of choice for anaphylactic shock

epinephrine, IM

anticholinergic drugs are contraindicated in patients with _____ because ____

glaucoma b/c they increase intraocular pressure

Therapeutic goal of drug therapy-Parkinson's disease:

improve the patient's ability to carry out activities of daily life. Drugs benefit the patient primarily by improving bradykinesia, gait disturbances, and postural instability.

The nurse is reviewing drugs on the emergency cart with regard to their therapeutic action. Which medications can help initiate heart contraction during a cardiac arrest?

intravenous epinephrine

Only drugs that are ____ or have a ____ can cross the BBB

lipid soluble; transport system

A ______ is administered in order to achieve plateau quickly with a drug. After high drug level is achieved, a plateau is maintained by administering smaller doses. The smaller doses are referred to as ________.

loading dose; maintenance doses

A nurse is preparing to give bethanechol (Urecholine). What is an expected outcome of this drug?

non distended bladder

Because of ease, convenience, and relative safety, _____ is generally preferred to _____ administration.

oral; parenteral

A woman in labor receives an opioid such as meperidine (Demerol) for pain. The nurse caring for the infant will observe the infant closely for which of the following?

respiratory depression

A ______ defined as a nearly unavoidable secondary drug effect produced at therapeutic doses. Common examples include drowsiness caused by traditional antihistamines and gastric irritation caused by aspirin.

side effect

Pharmacodynamics

study of how drugs affect the body

Adrenergic agonists are also called

sympathomimetic drugs

Propranolol is the prototype of ________, produces nonselective beta blockade. That is, this drug ____________.

the first-generation beta blockers; blocks both beta1- and beta2-adrenergic receptors

Maximal Efficacy

the largest effect a drug can produce

If administered at therapeutic doses, albuterol has minimal side effects. The most common is:

tremor

muscarinic receptors location and type of receptor

type: cholinergic receptor location: all parasympathetic organs

If administered in large doses, albuterol loses its selectivity and may cause _____

undesired cardiac stimulation

Potentiative

when a drug intensifies the effect of another

Epinephrine-therapeutic uses

• Because it can cause alpha1-mediated vasoconstriction, epinephrine is used to (1) delay absorption of local anesthetics, (2) control superficial bleeding, and (3) elevate blood pressure. In the past, epinephrine-induced vasoconstriction was also used for nasal decongestion. • Activation of alpha1 receptors on the iris can be used to produce mydriasis during ophthalmologic procedures. • Because it can activate beta1 receptors, epinephrine is used to (1) overcome AV heart block and (2) restore cardiac function in patients experiencing cardiac arrest. • Activation of beta2 receptors in the lung promotes bronchodilation, which can be useful in patients with asthma (although other drugs are preferred). • Because it can activate a combination of alpha and beta receptors, epinephrine is the treatment of choice for anaphylactic shock.

There are situations in which parenteral administration may be superior. These are:

• Emergencies that require rapid onset of drug action. • Situations in which plasma drug levels must be tightly controlled. (Because of variable absorption, oral administration does not permit tight control of drug levels.) • Treatment with drugs that would be destroyed by gastric acidity, digestive enzymes, or hepatic enzymes if given orally (eg, insulin, penicillin G, nitroglycerin). • Treatment with drugs that would cause severe local injury if administered by mouth (eg, certain anticancer agents). • Treating a systemic disorder with drugs that cannot cross membranes (eg, quaternary ammonium compounds). • Treating conditions for which the prolonged effects of a depot preparation might be desirable. • Treating patients who cannot or will not take drugs orally