Lisinopril versus lisinopril plus hydrochlorothiazide in essential hypertension

The efficacy of a new angiotensin converting enzyme inhibitor, lisinopril, used alone (group A) was compared with lisinopril plus hydrochlorothiazide (group B) in 26 patients with essential hypertension. Therapy with both regimens was equally effective in lowering blood pressure compared to placebo. Mean antihypertensive dose of lisinopril was lower when given in combination with hydrochlorothiazide than when given alone (48 +/- 6 vs 68 +/- 12 mg daily). Plasma renin activity increased in both groups of patients, but more in group B (p less than 0.05). Plasma aldosterone concentrations and serum uric acid levels were also higher in the group receiving lisinopril plus hydrochlorothiazide (p less than 0.05). Serum potassium concentrations were unaffected in either group. The incidence of side effects was similar in groups A and B (44% and 38%, respectively). This study suggests that lisinopril alone or in combination with hydrochlorothiazide effectively lowers blood pressure in patients with essential hypertension without any major side effects.