How is a drug described when it binds to a receptor and produces a desired response?

When a drug binds to a receptor and enhances its activity to produce a desired physiological response, it is referred to as an agonist. Agonists mimic the action of naturally occurring substances in the body, triggering the receptor to elicit a specific effect, such as activating pathways that can lead to a therapeutic outcome.

In contrast, a drug classified as an antagonist would bind to the receptor but would block or inhibit the action, preventing the desired effect from occurring. Inhibitors typically refer to substances that prevent a biochemical reaction, often relating to enzymes rather than receptor-mediated actions. The term "partial blocker" does not apply in this context; instead, it might describe a partial agonist, which only activates the receptor partially, producing a reduced response compared to a full agonist. Thus, the term that accurately describes a drug producing the desired response through receptor binding is indeed an agonist.