Metabolic effects of ACE inhibitors.

More than 10 years of clinical experience using angiotensin-converting-enzyme (ACE) inhibitors have shown that this class of drug does not have any adverse metabolic effects on carbohydrate and lipid metabolism. Rather, a number of studies on patients with essential hypertension or non-insulin-dependent diabetes mellitus have indicated minor improvements in glucose homeostasis and correction of dyslipidaemia. Some recent studies using the euglycaemic insulin clamp technique have indicated that the beneficial effect of captopril, the most extensively studied drug, is exerted on insulin sensitivity, a site with the potential to influence glucose and lipid metabolism. There is no uniform explanation for this action of captopril, but increased blood flow in skeletal muscle, accumulation of bradykinin or more efficient insulin release may be suggested as potential modes of action. It remains to be established whether this effect of captopril can be extrapolated to other ACE inhibitors, and the extent to which effects on insulin sensitivity will influence the long-term consequences for future risk of diabetes mellitus and coronary heart disease in patients with essential hypertension.