Antihypertensive drugs and glucose metabolism: a comparison between a diuretic and felodipine, a new calcium antagonist, when added to a beta-blocker in non-diabetic hypertensive women.

Felodipine, a vascular selective antihypertensive calcium antagonist, was compared with hydrochlorothiazide, a diuretic, with respect to glucose tolerance. An open crossover study was performed comprising 16 non-diabetic hypertensive women (age range 59-75 years). The women continued to take a beta-blocker as a basal therapy. Each treatment period lasted three months. The blood pressure was similar irrespective of treatment. Blood glucose values were not significantly different during the oral glucose tolerance test. Serum insulin levels after glucose administration were lower when the patients were treated with felodipine than when taking hydrochlorothiazide. A possible explanation for this observation may be an increased insulin release as a consequence of treatment with a diuretic in order to maintain normal blood glucose levels during the glucose tolerance test. Felodipine appears preferable to hydrochlorothiazide as an addition to a beta blocker in hypertensive patients from a glucose metabolism point of view.