NCIt definition : A prodrug and non-sulfhydryl angiotensin converting enzyme (ACE) inhibitor with antihypertensive
activity. Spirapril is converted in the body to its active metabolite spiraprilat.
Spiraprilat competitively binds to and inhibits ACE, thereby blocking the conversion
of angiotensin I to angiotensin II. This prevents the potent vasoconstrictive actions
of angiotensin II and results in vasodilation. Spiraprilat also decreases angiotensin
II-induced aldosterone secretion by the adrenal cortex, which leads to an increase
in sodium excretion and subsequently increases water outflow.;