Ontario Registered Pharmacy Technician (RphT) Practice Exam 2025 - Free RphT Practice Questions and Study Guide

A drug interaction is specifically defined as a situation where one drug affects the activity of another, which can occur in several ways, such as enhancing or inhibiting the effects of the other medication or altering how the body metabolizes one of the drugs. This definition encompasses various types of interactions, including pharmacodynamic interactions, where the effects of the drugs influence one another, and pharmacokinetic interactions, where one drug impacts the absorption, distribution, metabolism, or excretion of another.

While side effects of a drug pertain to the unwanted or adverse reactions of a single medication on the body, they do not define the interaction between two or more drugs. The combined use of over-the-counter medications can sometimes lead to interactions, but this term is broader than just interacting drugs—it does not specifically capture the essence of how one drug's action influences another. Similarly, a reaction between a drug and food refers to food interactions, which, although important, are distinct from drug-drug interactions that are the focus of this question. Thus, the first statement accurately captures the concept of drug interactions within the realm of pharmacology.