Enalaprilat

Enalaprilat is the active metabolite of the orally available pro-drug, enalapril. Used in the treatment of hypertension, enalapril is an ACE inhibitor that prevents Angiotensin Converting Enzyme (ACE) from transforming angiotensin I into angiotensin II. As angiotensin II is responsible for vasoconstriction and sodium reabsorption in the proximal tubule of the kidney, down-regulation of this protein results in reduced blood pressure and blood fluid volume. Enalaprilat was originally created to overcome the limitations of the first ACE inhibitor, captopril, which had numerous side effects and left a metallic taste in the mouth. Removal of the problematic thiol group from captopril resulted in enalaprilat, which was then modified further with an ester to create the orally available pro-drug enalapril.

Enalaprilat is poorly orally available and is therefore only available as an intravenous injection for the treatment of hypertension when oral therapy is not possible.