A comparative study on efficacy, tolerability, and some metabolic side-effects of propranolol and hydroflumethiazide in adult African patients with mild to moderate hypertension

Abstract

A prospective study to compare propranolol monotherapy and hydroflumenthiazide monotherapy in adult African patients with essential mild to moderate hypertension was carried out at Kenyatta National Hospital. 60 men and women aged between 22 and 65 years and with blood pressures ranging from 130/100mmHg to 180/110mmHg were enrolled. Patients with obstructive airway disease, heart failure, diabetes mellitus, hepatic disease and renal disease were excluded. They all underwent history taking, physical examination, baseline serum potassium, uric acid, fasting glucose and lipid profiles, and electrocardiogram (ECG). They were then randomnly assigned to either of the two treatment regimmens and followed-up 4-weekly for 12 weeks with serial monitor of symptoms, blood pressure, pulse and repeat ECG and serum bicohemsitry at end of week -12. Bias in blood pressure recordings was removed by the use of a randornn-osphygmomanometer and laboratory analysis of specimens was blinded. Hydroflumethiazide was significantly more effective in lowering diastolic blood pressure than propranolol (p < 0.01). Neither of the two drugs produced any ECG - left ventricular hypertrophy regression. Hydroflumethiazide was more associated with palpitations, sweating and impotence while propranolol was more associated with exertionaI dyspnoea and Raynaud's phenomenon. Hydroflumethiazide treatment was also associated with significant increases in total serum cholesterol, low-density-lipoproteins (LDL) cholesterol, serum uric acid levels and fasting serum glucose levels (p < 0.001); and significant fall in potassium levels (p < 0.01). In the propranolol treated patients, very low-density lipoproteins (VLDL) and total serum triglycerides rose significantly and HDL-cholesterol levels also declined significantly (p < 0.01).

Propranolol had no significant effect on all the cardiovascular risk factors studied. Hydroflumethiazide significantly reduced the number of patients with hypertension (BP > 140/90 mmHg) but also significantly increased the number of patients with hyperuricaemia. The cost of propranolol treatment was three times that of hydroflumethiazide treatment. The use of beta-blocker monotherapy in black Kenyan patients with mild to moderate hypertension is not recommended. Thiazide monotherapy is effective and cheap but its metabolic side-effects need further studies to determine their significance in the Kenyan set-up.