FELODIPINE EXTENDED-RELEASE VERSUS CONVENTIONAL DIURETIC THERAPY FOR THE TREATMENT OF SYSTOLIC HYPERTENSION IN ELDERLY PATIENTS

Objective: To compare 8 weeks of monotherapy using either felodipine e xtended release (ER) or a conventional diuretic therapy, triamterene/h ydrochlorothiazide (HCTZ), in elderly patients with systolic hypertens ion. Design: Prospective, randomized, single-blind screening, double-b lind treatment, parallel group comparison. Setting: Twenty-nine genera l and family practice sites across Canada. Participants: Men and post- menopausal women aged 60 to 85 years, with mild to moderate primary sy stolic hypertension (systolic blood pressure > 160 mm Hg or blood pres sure > 140/ > 90 mm Hg). Interventions: Daily doses of either felodipi ne ER (2.5 mg) or triamterene/HCTZ (25/12.5 mg) for 8 weeks. After the first 4 weeks, the patients who responded to the initial dosage (a re duction in systolic blood pressure of at least 15 mm Hg) or whose bloo d pressure was controlled on ths dosage (systolic blood pressure < 140 mm Hg) continued to take the low dose. Among the others, the daily do ses were doubled for the final 4 weeks. Outcome measures: Systolic blo od pressure before beginning treatment and at the end of the study, as well as adverse events and results of heart rate measurement, clinica l chemistry tests, electrocardiograms and physical examination before and after therapy. Results: Sufficient data for analysis were obtained from 216 patients (86 men and 130 women). Mean seated blood pressure was reduced significantly in both the felodipine group (from 168/91 to 151/84 mm Hg) and the diuretic group (from 168/92 to 147/84 mm Hg). T he difference in mean reductions in systolic blood pressure between th e groups was 2.2 mm Hg (with a 95% confidence interval of -1.7 to 6.0 mm Hg), which was not significant. Clinical chemistry measurements tak en before treatment and at the end of the study showed that more patie nts in the diuretic group developed abnormal values for blood urea nit rogen, uric acid and creatinine. Other changes were unremarkable. The incidence of adverse events was similar in both groups, but more patie nts in the felodipine group (9) than in the diuretic group (3) discont inued treatment owing to an adverse event. Conclusions: Felodipine ER (2.5 to 5 mg daily) is as effective in reducing systolic blood pressur e as triamterene/HCTZ (25/12.5 mg to 50/25 mg daily). More patients di scontinued felodipine treatment than traimterene/HCTZ treatment owing to adverse events. However, patients receiving triamterene/HCTZ tended to have abnormal levels in clinical chemistry tests; these should be monitored.