~-Blockers, Diuretics or Both for Control of Hypertension? Acebutolol and hydrochlorothiazide are of equal efficacy in this multicentre study

Following a 3-week placebo washout, 360 patients, aged 21-75 years, from 19 centres who had mild to moderate essential hypertension [sitting diastolic BP (phase 5) 95-114mm Hg] were randomised in double­blind fashion to 12 weeks' treatment with either acebutolol 400-1200 (mean 757) mg/day (n = 182) or hydrochlorothiazide 50-100 (mean 66.7) mg/day (n = 178).

Acebutolol and hydrochlorothiazide significantly reduced mean sitting BP from 153/101 to 137/86mm Hg and from 153/101 to 135/87mm Hg, respectively. 72% and 63% of acebutolol and hydrochlorothiazide recipients, respectively, achieved either a diastolic BP ::::; 90mm Hg or a ~ 10% reduction from baseline. Acebutolol reduced mean heart rate by 11.5% (8.9 beats/min). Hydrochlorothiazide transiently increased mean heart rate, dose-dependently (p = 0.001 compared with acebutolol).

65 and 67 patients withdrew from acebutolol and hydrochlorothiazide therapy, respectively, including 14 patients from each group who withdrew because of side effects. Significantly more patients receiving hydrochlorothiazide than acebutolol reported arrhythmias, anorexia, flatulence and nocturia. Biochemical changes in serum glucose (increased) and potassium (decreased) in hydrochlorothiazide-treated patients, and serum cholesterol (decreased) acebutolol-treated patients may have clinical relevance. Asymptomatic positive antinuclear antibody tests of low titre developed (~ 1 : 40) in 11 and 3 patients receiving acebutolol and hydrochlorothiazide, respectively. Wahl J. Smgh BN. Thaden WR Amencan Heart Journal 111. 353-362. Feb 1986

Atenolol + chlorthalidone is as effective as either drug alone and hypokalaemia is avoided In a double-blind crossover trial, 28 outpatients with mild to moderate hypertension randomly received

ate nolo I 50 or 100mg daily, chlorthalidone 12.5mg daily or atenolol + chlorthalidone 50mg/12.5mg daily for 3 weeks each in a crossover design. The study was preceded by a 4-week placebo washout and each treatment was separated by a single-blind placebo washout.

Supine BP was significantly reduced by all 4 treatments. The atenolol + chlorthalidone was more effective than atenolol 100mg daily in reducing supine and standing systolic BP and more effective than atenolol 50mg daily in reducing standing systolic BP. Diastolic BP was < 90mm Hg in 22 patients on the combination compared with 14, 16 and 14 patients on atenolol low and high dose and chlorthalidone alone, respectively. Serum potassium levels were reduced with chlorthalidone alone but not when combined with atenolol. Reported side effects with all treatments were mild and similar in frequency to those reported with placebo. The authors conclude that a low-dose atenolol + chlorthalidone combination is ' ••• effective and well tolerated for treatment of patients with mild to moderate hypertension'. Leonetti G. Pasotti C. Capra A. International Journal of Clinical Pharmacology. Therapy and Toxicology 24: 4347. Jan 1986

BP is controlled with chlorthalidone plus either atenolol or labetalol In an open trial, 22 previously untreated patients with mild to moderate hypertension received labetolol + chlorthalidone 2OOmg/20mg daily for 1 month followed after a 15-day washout period by atenolol+ chlorthalidone 100mg/25mg daily for a further month.

Supine BP decreased from 146/103 to 137/93mm Hg with labetolol + chlorthalidone and from 148/105 to 132/88mm Hg with atenolol + chlorthalidone. The 2 combinations were not significantly different. BP normalisation (diastolic BP < 90mm Hg) was achieved in 9 patients on the labetolol and on the atenolol combination. On exercise testing, BP and heart rate at maximal effort were lower with atenolol + chlorthalidone and the level of muscular exertion before exhaustion was also reduced. Side effects were of similar incidence for both treatments but a greater number of severe effects were reported with atenolol. Roja M. Cumetti C. Vergani A. Montanan C, De Cristofar A. Drugs under Experimental and ClInical Research 11: 815-860. Feb 1986.

0156-2703/86/1005-0009/0$01.00/0 © ADIS Press INPHARMA® 15 Mar 1986 9