direct-acting
"Direct-acting" refers to a type of medication or treatment that works immediately on the target area or system without needing to be converted or processed by the body. For example, in the context of pain relief, direct-acting medications provide quick relief by acting directly on pain receptors.
In the field of pharmacology, direct-acting agents can include certain types of antihypertensives that lower blood pressure by directly relaxing blood vessels. This immediate action contrasts with indirect-acting agents, which may require metabolic processes to achieve their effects.