Sinopril, (lisinopril), lysine analogue of enalaprilat, is a peptidyl dipeptidase inhibitor. It inhibits the angiotensin-converting enzyme (ACE) that catalyses the conversion of angiotensin I to the vasoconstrictor peptide, angiotensin II.Sinopril, (lisinopril), is indicated as:-Treatment of hypertension, either alone as initial therapy or concomitantly with other classes of antihypertensive agents.-Adjunctive therapy in the management of heart failure in patients who are not responding adequately to diuretics and digitalis.-Treatment of hemodynamically stable patients within 24 hours of acute myocardial infarction, to improve survival.