What is antagonism in drug interactions?

Antagonism in drug interactions refers to two drugs that compete for the same receptors. This concept is critical in pharmacology, as it helps explain how different drugs can influence each other's effects when administered together. When two drugs act as antagonists, they typically diminish or counteract each other's pharmacological effects, which can lead to reduced therapeutic efficacy or unexpected outcomes in treatment.

For instance, if one drug is intended to activate a receptor to elicit a response, and another drug competes for that same receptor but does not activate it, the presence of the antagonist would impair the first drug's desired effect. Understanding this competition is essential for clinicians in order to optimize drug combinations and avoid potential therapeutic failures.

In contrast, the other options describe different aspects of drug interactions. Enhancement of one drug's effect by another refers to synergism, while the collaboration of drugs to treat an infection embodies the concept of synergy or additive effects. The idea of toxicity from drug combinations highlights potential adverse effects rather than the specific mechanism of receptor competition that defines antagonism.