The effects of bendroflumethiazide added to nifedipine in patients with hypertension.

It has been suggested that a diuretic added to a calcium antagonist may not reduce blood pressure further in patients with hypertension. Bendroflumethiazide 5 mg was given to 17 patients with essential hypertension who had persistent mild to moderate hypertension despite treatment with nifedipine slow-release tablets 20 mg bid. One group received bendroflumethiazide before (N = 8) and the other after placebo (N = 9) in a double-blind, randomized cross-over trial. Supine blood pressure following active bendroflumethiazide administration was significantly reduced in both groups compared with trial entry (166/105 to 150/96 mm Hg, P less than .01; 170/108 to 156/98 mm Hg, P less than .01). A reduction in serum potassium level and a rise in serum uric acid concentration were seen with combined treatment. We cannot substantiate theoretic arguments for the ineffectiveness of a bendroflumethiazide-nifedipine combination on blood pressure.