Medications that stimulate an effect are called?

• A. Antagonists
• B. Agonists
• C. Modulators
• D. Inhibitors

Answer: (B)

Medications that stimulate a response by binding to receptors are called agonists. They mimic the body’s natural signaling molecules and activate the receptor to produce a cellular effect. The strength of the response depends on the agonist’s efficacy: a full agonist can elicit a maximal response, while a partial agonist produces a smaller effect even when it fully occupies the receptor. For example, epinephrine acts as an agonist at adrenergic receptors and increases heart rate and contractility.

Antagonists, by contrast, block receptors and prevent activation, so they don’t produce a stimulating effect. Modulators can influence how strongly or how often a receptor responds but don’t necessarily cause direct activation. Inhibitors reduce activity by blocking enzymes or pathways rather than directly activating receptors.