A parallel study of enalapril and captopril and 1 year of experience with enalapril treatment in moderate-to-severe essential hypertension

Angiotensin converting enzyme (ACE) inhibitors, enalapril (5 to 20 mg twice daily) or captopril (25 to 100 mg thrice daily) and matching ACE inhibitor placebos were given to 32 moderate-to-severe essential hypertension patients who were already on 50 mg hydrochlorothiazide daily. Alpha-methyldopa (250 to 500 mg twice daily) was given to 16 patients following 6 weeks of ACE inhibitor therapy. Both enalapril and captopril significantly (p less than 0.05) lowered the supine and upright blood pressures (BPs) (acutely and long-term) without significant reflex heart rate changes. The BPs of enalapril patients were, however, significantly lower (supine diastolic p less than 0.03, supine systolic p less than 0.05, and upright diastolic p less than 0.04) than those of captopril patients when compared by repeated measures of analysis of variance. Eleven enalapril patients have been followed for 1 year with continued BP control. Skin rash occurred in one captopril patient and reversible renal insufficiency developed in two enalapril patients during the first 16 weeks. It is concluded that (although both ACE inhibitors lowered BP, enalapril was more effective than captopril and twice-daily enalapril was well tolerated during 52 weeks of treatment.