Question

is captopril agonist, antagonist, competitive, non-competitive and why

Answer 1

Captopril is a antagonist and competitive inhibitor of Angiotensin converting enzyme (ACE), the enzyme responsible for the conversion of angiotensin I to angiotensin II in kidney, blood vessels, heart, brain and adrenal gland.

Captopril binds to the active site of angiotensin converting enzyme and thereby prevents the binding of angiotensin I to the enzyme, thus block the conversion of angiotensin I to angiotensin II (active form of angiotensin that stimulate aldosterone release). This leads to an increase in the amount of sodium and urine excreted, reduced resistance in kidney blood vessels, an increase in venous capacity and decreases in cardiac output, stroke work and volume (lowers blood pressure).