ACE inhibitors are very similar, and all are effective for treating hypertension. Some are eliminated primarily by the kidneys while others are also eliminated in bile and feces . This difference in elimination may be important in choosing among ACE inhibitors in patients with reduced kidney or liver function, who may accumulate drugs that are excreted via the kidneys or liver. Except for captopril (Capoten) and lisinopril (Prinivil, Zestril), ACE inhibitors are inactive until they are converted to an active form in the body.
ACE inhibitors possess many common characteristics with another class of cardiovascular drugs, angiotensin II receptor antagonists , which are often used when patients are intolerant of the adverse effects produced by ACE inhibitors. ACE inhibitors do not completely prevent the formation of angiotensin II, as blockage is dose-dependent, so angiotensin II receptor antagonists may be useful because they act to prevent the action of angiotensin II at the AT 1 receptor, leaving AT 2 receptor unblocked; the latter may have consequences needing further study.