Angiotensin converting enzyme inhibition in hypertension

An examination of the principal physiological actions of angiotensin II should make it clear why in vivo attempts to inhibit the rate of angiotensin II generation have been an attractive avenue in pursuing control of high blood pressure. The major physiological effect of angiotensin II relates to its direct pressor effect, but there are supplementary blood pressure regulating actions. Therefore, if we limit the rate of angiotensin II generation by inhibiting the angiotensin converting enzyme (ACE) we should expect to control high blood pressure in a number of clinical syndromes. This paper reviews the future of ACE inhibitors in the treatment of conditions such as hypertension associated with unilateral renal artery stenosis, essential hypertension and severe and previously unresponsive hypertension, with respect not only to efficacy but also to the side-effect profile and ancillary properties. Side effects seen with this class of drug are cough, rashes (both morbilliform and urticarial) and, rarely, angio-oedema. Proteinuria, nephrotic syndrome, leukopenia and taste disturbance were previously reported with captopril but only taste disturbance, and that less frequently, is apparent at the lower doses now employed. Several studies have examined the 'quality-of-life' aspects of ACE therapy and have usually but not always reported favourably. There are features of the ACE inhibitors which make them attractive drugs, and while we should be cautious because of limited experience, we should critically and creatively examine their properties over the next years.