When considering the pharmacotherapeutic effects of drugs administered to clients, the nurse considers which property of most importance:
A. Efficacy.
B. Interaction with other drugs.
C. Potency.
D. Toxicity.
Correct Answer: A. Efficacy
In pharmacology, efficacy is the maximum response achievable from a drug. Efficacy is the capacity to produce an effect (eg, lower blood pressure). Efficacy can be assessed accurately only in ideal conditions (ie, when patients are selected by proper criteria and strictly adhere to the dosing schedule). Thus, efficacy is measured under expert supervision in a group of patients most likely to have a response to a drug, such as in a controlled clinical trial.
Option B: Drug-drug interactions occur when two or more drugs react with each other. This drug-drug interaction may cause you to experience an unexpected side effect. For example, mixing a drug you take to help you sleep (a sedative) and a drug you take for allergies (an antihistamine) can slow your reactions and make driving a car or operating machinery dangerous.
Option C: Potency is an expression of the activity of a drug in terms of the concentration or amount of the drug required to produce a defined effect.
Option D: Toxicity refers to how poisonous or harmful a substance can be. In the context of pharmacology, drug toxicity occurs when a person has accumulated too much of a drug in his bloodstream, leading to adverse effects on the body.