Captopril: a preliminary review of its pharmacological properties and therapeutic efficacy

Captopril is the first orally active inhibitor of angiotensin-converting enzyme to become available. It has been studied primarily in hypertension. In mild to moderate essential hypertension captopril is about as effective as usual doses of hydrochlorothiazide or propranolol, about one-half of such patients needing the addition of a diuretic to achieve satisfactory control of blood pressure. In severe hypertension captopril plus a diuretic (and in some patients a beta-blocker) usually reduced blood pressure significantly more than could be achieved with 'standard triple therapy' in patients not responding adequately to such a regimen, and often resulted in an improved feeling of well-being in severely hypertensive patients previously receiving intensive multiple drug therapy. Indeed, at the present stage of the drug's development, patients not responding to or not tolerating 'traditional' antihypertensive therapy represent the most suitable candidates for captopril treatment. While captopril has been well tolerated in most patients, some troublesome or potentially serious side effects have been reported, including agranulocytosis, dysgeusia and reduced renal function; although a clear causal relationship with captopril was not always established, it would appear that the final place of captopril in the treatment of hypertension may ultimately depend on further clarification of its adverse effects profile. In addition to studies in hypertension, captopril has produced encouraging improvement in a small number of patients with severe congestive heart failure resistant to conventional therapy. Captopril must be considered an exciting addition to the therapeutic armamentarium; it, and pharmacologically related compounds of the future, will continue to generate much interest as their final place in therapy becomes better defined through additional well designed studies and wider clinical experience.