Comparison of enalapril and thiazide diuretics in the elderly hypertensive patient.

One hundred seventy-four patients, 65 years of age or older, entered a double-blind, seven-center, 16-week, controlled study to compare the effects of enalapril and hydrochlorothiazide (HCTZ) in an elderly hypertensive population. Sixty-eight percent of the patients were men, 32% were women. Thirty-two percent of the patients had isolated systolic hypertension. Approximately 80% of the patients were white. After a 4-week placebo run-in period, patients with sitting diastolic BP (DBP) of 90-120 mm Hg or systolic BP (SBP) greater than or equal to 160 mg Hg and DBP less than 90 mm Hg (isolated systolic hypertension) were randomized to receive 10 mg of enalapril or 12.5 mg of HCTZ once daily. If after 4 weeks their BPs were not controlled (i.e., DBP greater than 85 mm Hg or SBP greater than 140 mm Hg), the dose of the drug was doubled. If after successive 4-week intervals, their BPs were still not controlled, the other drug was added to their regimen and this was then doubled. The initial mean BPs were 167/94 mm Hg in both groups. By the end of the monotherapy phase at 8 weeks, the mean BPs had fallen significantly (p less than or equal to 0.01) to 148/85 mm Hg in both groups. By 16 weeks, the mean BPs had again fallen similarly: in the enalapril group to 144/83 mm Hg, and in the HCTZ group to 145/83 mm Hg. Seventy-nine percent of the enalapril group and 85% of the HCTZ group had controlled BPs at this time (DBP less than or equal to 85 or SBP less than or equal to 140 mm Hg). White and nonwhite patients in both drug groups had similar falls in SBP and DBP both at the end of the monotherapy period and the overall study. The white patients experienced more rapid falls in BP with enalapril, the nonwhite patients with HCTZ. Three serious adverse experiences occurred in the enalapril group, none of which were considered likely to be due to the drug therapy. Overall, 49% of the enalapril group and 61% of the HCTZ group reported an adverse effect during the study (not significant). Laboratory adverse effects occurred 10% more frequently in the HCTZ group: enalapril, 22%; HCTZ, 32% (not significant); none was serious. Both drugs therefore appeared to be equally efficacious antihypertensive agents in these elderly patients.