Metabolic considerations in the approach to diabetic hypertensive patients

The effects of antihypertensive drugs on glucose metabolism are an important consideration in the selection of pharmacologic therapy for diabetic patients. Diuretics can elevate blood glucose levels, aggravate glucose intolerance, and predispose diabetic patients to hyperosmolar non-ketotic coma. Beta-blocking drugs often exacerbate and prolong insulin-induced hypoglycemia in diabetics. Beta-blockers may also cause hyperglycemia. Central agonists, alpha-blockers, and vasodilators apparently have neutral effects on carbohydrate metabolism in normal subjects or in hypertensive diabetics. Calcium channel blockers may disturb carbohydrate metabolism in diabetic patients. Angiotensin-converting enzyme inhibitors have little effect on glucose metabolism. Because diabetic patients are prone to fluid, electrolyte, hormone, and lipid disturbances, it is important to consider the effects of antihypertensive drugs on these aspects of metabolism when selecting pharmacologic therapy. The effects of various antihypertensive drugs on sodium, calcium, magnesium, and acid/base balance are reviewed. The effects of these drugs on serum uric acid and potassium, as well as on hormone and lipid levels, are also considered.