Monotherapy with amlodipine or hydrochlorothiazide in patients with mild to moderate hypertension: Comparison of their efficacy and effects on electrolytes

Background Amlodipine and hydrochlorothiazide (HCTZ) are commonly prescribed in Nigeria, either as a monotherapy or in combination with other drugs. The present study was designed to investigate the antihypertensive efficacy of monotherapy with amlodipine or HCTZ and their effects on electrolyte profile in patients with mild to moderate hypertension. Methods A single-blind randomised clinical study design was used; 50 patients newly diagnosed with mild to moderate hypertension (aged 33 to 60 years) were recruited and divided into 2 groups (each with 25 subjects): amlodipine or hydrochlorothiazide. The subjects received either 5 mg of amlodipine or 25 mg of HCTZ, in their respective group, once daily for 4 weeks. Blood pressure and serum and urine electrolytes were measured at baseline and weekly throughout the experiment. Results At the end of follow-up, amlodipine reduced systolic and diastolic blood pressure significantly more (P < 0.001) than HCTZ. At the end of follow-up, blood pressure was reduced to normal in 80% of the subjects in the amlodipine group, compared to 50% in the HCTZ group. Amlodipine had no significant effect on electrolyte profiles, unlike HCTZ, which significantly changed both serum and urine electrolytes. Conclusions Monotherapy with amlodipine was more effective than HCTZ in patients with mild to moderate hypertension and in addition maintained electrolyte balance.