Pharmacology Lecture: Adverse Drug Reactions & Interactions

Flashcards covering major concepts from the lecture: pharmacological vs therapeutic actions, side effects, ADRs, drug interactions, food interactions, lifespan considerations, polypharmacy, and patient education.

What is meant by the expected pharmacological action of a drug?

It is the specific effect the drug is designed to exert in the body—its mechanism of action.

What is meant by the therapeutic use of a drug?

The clinical reason the drug is given—the desired outcome for the patient (e.g., infection control, pain relief).

Give an example of one drug with two therapeutic uses discussed in class.

Ibuprofen—used to reduce fever and to decrease inflammation/pain.

Define a side effect.

An unwanted but frequently predictable effect that occurs in addition to the desired therapeutic effect (e.g., Benadryl causing drowsiness).

Define an adverse drug reaction (ADR).

An unintended, unexpected, and potentially harmful reaction that occurs at normal drug doses (e.g., anaphylaxis to penicillin).

Differentiate primary vs. secondary adverse drug actions.

Primary: from overdose or excessive pharmacological action. Secondary: additional effects unrelated to the desired action but produced by the drug.

Why is Coumadin (warfarin) overdose dangerous?

Excess anticoagulation can prevent clotting and cause uncontrolled bleeding.

List two common CNS adverse reactions.

Agitation/confusion or seizures/sedation.

Which two organs are most important for metabolism and excretion of drugs?

Liver (metabolism) and kidneys (excretion).

What is drug hypersensitivity?

An immune-mediated allergic response that appears after repeated exposure, ranging from rash to anaphylaxis.

Name three classic signs of anaphylactic shock.

Facial/lip swelling, throat tightness or wheezing, rapid drop in blood pressure (tachycardia possible).

Define teratogenicity.

The ability of a drug to cause fetal abnormalities when taken during pregnancy.

Explain drug tolerance.

A decreased physiological response to a drug over time, requiring higher doses to achieve the same effect.

Explain cumulative drug effect.

Drug levels build up because absorption exceeds metabolism/excretion—often occurs in liver or kidney impairment.

Define drug toxicity.

Harmful, life-threatening effects produced by excessive drug levels; may be irreversible (e.g., vancomycin ototoxicity).

What is meant by a drug precaution?

The drug may be used but with careful monitoring due to higher risk in certain populations or conditions.

What is a contraindication?

A situation in which a drug must NOT be given because risk clearly outweighs benefit (e.g., penicillin allergy).

Describe an antagonist drug interaction.

One drug blocks or decreases the effect of another (e.g., a cardiovascular drug constricting airways blocks an asthma bronchodilator).

Describe an additive drug interaction.

Two drugs with similar actions produce a combined effect equal to the sum of each (e.g., alcohol + sedative = more sedation).

Describe a synergistic drug interaction.

Two drugs with different actions produce an effect greater than either alone (e.g., Pepcid + Prevacid for reflux).

What is an agonist drug?

A drug that binds to a receptor and mimics or enhances the body’s own substance, increasing the cellular response.

How can grapefruit juice affect certain medications?

It inhibits liver enzymes, limiting metabolism and increasing blood levels, risking toxicity.

Why should patients on warfarin limit high-vitamin-K foods like spinach?

Vitamin K promotes clotting and antagonizes warfarin’s anticoagulant effect, decreasing drug activity.

Give an example of food increasing drug absorption.

Vitamin C (orange juice) increases iron absorption.

Which life-span groups require dose adjustments based on weight and body surface area?

Infants and children.

List two physiological changes in the elderly that alter drug handling.

Reduced kidney/liver function and decreased GI motility/cardiac output.

Define polypharmacy.

Use of multiple medications simultaneously, common in older adults, increasing risk of interactions and ADRs.

State two strategies to improve medication adherence in the elderly.

Use pill organizers (AM/PM boxes) and simplify regimens or schedules.

What key information should nurses include when providing medication teaching?

Purpose, generic/brand name, dose/schedule, administration technique, possible adverse effects, and precautions (e.g., foods to avoid).

Why is return demonstration important in client teaching?

It lets the nurse verify the patient understands and can correctly perform the medication administration technique (e.g., insulin injection).