Benazepril is a prodrug which is metabolized by the liver into its active form benazeprilat via cleavage of the drug's ester group. Benazepril and Benazeprilat inhibit angiotensin-converting enzyme (ACE) in human subjects and animals. Benazeprilat has much greater ACE inhibitory activity than does Benazepril. It is indicated for the treatment of hypertension. It may be used alone or in combination with thiazide diuretics. Adverse reactions reported in controlled clinical trials and rarer events seen in post-marketing experience, include the following: Stevens-Johnson syndrome, pemphigus, apparent hypersensitivity reactions (manifested by dermatitis, pruritus, or rash), photosensitivity, and flushing, nausea, pancreatitis, constipation, gastritis, vomiting, and melena, thrombocytopenia and hemolytic anemia, anxiety, decreased libido, hypertonia, insomnia, nervousness, and paresthesia. Patients on diuretics, especially those in whom diuretic therapy was recently instituted, may occasionally experience an excessive reduction of blood pressure after initiation of therapy with Benazepril. Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving ACE inhibitors (including benazepril) during therapy with lithium.