Massachusetts Pharmacy Technician License Practice Test

What term describes a substance that inhibits or interferes with a biological action?

1. Agonist

2. Antagonist

3. Synergist

4. Modifier

The correct answer is: Antagonist

The term that describes a substance that inhibits or interferes with a biological action is "antagonist." In pharmacology, an antagonist is a type of drug or compound that binds to a receptor and blocks or dampens the biological response that would normally be triggered by an agonist. This mechanism is essential in various therapeutic applications, especially when the goal is to counteract excessive physiological responses or to modulate the effects of other substances. In contrast, an agonist is a substance that promotes or enhances a biological action, acting as a trigger for receptor-mediated responses. A synergist refers to substances that, when combined, produce a greater effect than they would individually, and a modifier typically refers to substances that alter the actions or effects of another substance without specifically categorizing their effects as inhibitory or enhancing. Thus, the definition and function of an antagonist clearly align with the concept of inhibiting or interfering with biological actions.