ANTIHYPERTENSIVE EFFECTS OF AMLODIPINE AND HYDROCHLOROTHIAZIDE IN ELDERLY PATIENTS WITH AMBULATORY HYPERTENSION

Recent studies and authorities have advocated the use of low-dose thia zide diuretics as first-line treatment agents in elderly hypertensives . However, these recommendations were based solely on blood pressure ( BP) measured in the clinic. The objective of the present 32-week doubl e-blind study was to compare the effects of hydrochlorothiazide (HCTZ) and amlodipine (AML) in elderly patients with confirmed ambulatory hy pertension. After a 4-week placebo washout period, 42 (25 men, 17 wome n) patients (mean age, 69 years) with clinic sitting diastolic BP of 9 5 to 114 mm Hg and daytime ambulatory diastolic BP of greater than or equal to 90 mm Hg were randomized double-blind to receive AML 5 to 10 mg (n = 21) or HCTZ 12.5 to 25 mg (n = 21) once daily. After 8 weeks o f monotherapy, patients in whom clinic diastolic BP remained greater t han or equal to 90 mm Hg were given combination therapy with the other agent. Amlodipine monotherapy induced significant reductions in clini c, mean 24-h, daytime and sleep systolic/diastolic BPs whereas only cl inic BP decreased significantly in patients treated with HCTZ monother apy. Moreover, 19/21 versus 8/21 patients on AML and HCTZ monotherapie s achieved adequate BP control. At the end of the 32-week treatment pe riod, combination therapy in the HCTZ group resulted in statistically significant reductions in clinic as well as in 24-h, daytime and sleep ambulatory BPs that were similar to those observed in the AML monothe rapy group. In conclusion, the administration of AML monotherapy induc ed significant reductions in both clinic and ambulatory BPs in elderly patients whereas only clinic BP was significantly decreased by HCTZ m onotherapy. Moreover, the addition of AML to HCTZ in patients inadequa tely controlled by monotherapy has permitted statistically significant decrements in clinic as well as in ambulatory BP. Consequently, the r esults of the present study suggest that the use of HCTZ in doses of u p to 25 mg daily is inadequate for ambulatory BP control in the elderl y despite official recommendations.