Captopril: an update review of its pharmacological properties and therapeutic efficacy in congestive heart failure.

Captopril is the first angiotensin-converting enzyme inhibitor for oral administration. In combination with continued digitalis and diuretic therapy it has been demonstrated to be effective in the management of severe heart failure refractory to optimal digitalis, diuretic and, in many patients, vasodilator treatment. Most studies to date have been open trials of several weeks or months duration, but a number of patients have received continued treatment, with sustained benefit, for up to 1 year or more. A placebo-controlled trial in a limited number of patients with less severe heart failure has confirmed the results of open trials. Captopril administration improves cardiac performance as a result of a reduction in systemic vascular resistance (afterload) and the various determinants of left ventricular filling pressure (preload). Improvements in exercise tolerance and functional classification, with associated reduction of clinical symptomatology, occur with simultaneous decreases in myocardial oxygen consumption. At present, captopril is worthy of a trial in patients refractory to more traditional medical management. Whether it should be considered a 'first-line' agent after failure of optimal digitalis and diuretic therapy, and before instituting other vasodilator therapy, is less clear. In patients with severe or resistant heart failure, a response to captopril is usually accompanied by a general improvement in the quality of life. The effect of captopril treatment on 1- and 2-year survival rates in patients with severe heart failure appears similar to that reported for other vasodilators. Most patients tolerate captopril treatment well, but hypotension, reduced renal function, skin rash, dysgeusia, and neutropenia have been reported.