Lisinopril Anhydrous is the anhydrous form of the long-acting angiotensin-converting enzyme (ACE) inhibitor lisinopril with antihypertensive activity. Lisinopril, a synthetic peptide derivative, 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. Lisinopril also decreases angiotensin II-induced aldosterone secretion by the adrenal cortex, which leads to an increase in sodium excretion and subsequently increases water outflow.