Enalapril: compares well with hydrochlorothiazide in hypertension

This study was designed to assess the hypotensive, metabolic and renal effects of enalapril hydrochlorothiazide and a combination of both in the first-line treatment of patients with essential hypertension. After a 4-week placebo run-in period 16, 15 and 8 patients were randomised to treatment with either enalapril 10-20 (mean 15)mg bid , hydrochlorothiazide 25-50 (mean 45)mg bid or enalapril (10-20mg) + hydrochlorothiazide (25-50mg), respectively.

There were similar significant reductions in blood pressure with each treatment regimen. Heart rate was increased with combination therapy but decreased during both monotherapy treatments . During .enalapril mono therapy there were significant increases in serum potassium, plasma renin activity and free-water clearance and decreases in plasma angiotensin II, total protein excretion, creatinine clearance, filtration fraction and urine osmolality. The significant changes associated with hydrochlorothiazide monotherapy included decreases in serum sodium, potassium, and chloride, and free­water clearance and increases in plasma renin activity , total CO2 content , fasting glucose, uric acid, serum urea nitrogen, sodium and potassium clearance , ffactional excretions and urine osmolality. Combination therapy resulted in significant decreases in serum sodium, potassium and chloride, plasma angiotensin II and filtration fraction and increases in plasma renin activity, plasma aldosterone and fraction of potassium excreted. 'No side effects were reported by any patients throughout the protocol.'

Single-drug therapy with enalapril 10-20mg bid was an effective antihypertensive regimen in these patients. It showed comparative efficacy to hydrochlorothiazide. The combination therapy at lower individual doses was equally effective and good patient tolerability was shown. It also may be effective in reducing some of the renal and volume related side effects of diuretic therapy. Bauer. JH. and Jones. LB .. American Journal of Kidney Diseases 4: 55 (Jul 1984)

6 INPHARMA® 13 Oct 1984 0156_2703/ 84/ 1013-0006/ 0$01 .00/ 0 © ADIS Press