Smooth blood pressure control obtained with extended-release felodipine in elderly patients with hypertension: evaluation by 24-hour ambulatory blood pressure monitoring

OBJECTIVE: To assess, by smoothness index (SI), distribution of the antihypertensive effect of extended-release (ER) felodipine over 24 hours in elderly patients with hypertension. METHODS: After a 4-week washout phase, 35 elderly patients (mean age 69 +/- 4 years) with mild-to-moderate hypertension received 2 weeks' treatment with ER felodipine 5mg once daily. The dosage of ER felodipine was doubled to 10 mg/day and given for a further 2 weeks in non-responders (sitting clinic blood pressure > 140/90mm Hg). The study had an open-label design with no placebo control. After each period, clinic and ambulatory blood pressures were measured. Trough-to-peak (T/P) ratio was computed by dividing the blood pressure (BP) change at trough (22 to 24 hours after drug intake) by the change at peak (2 adjacent hours with a maximal BP reduction between the second and eighth hour after drug intake). SI was calculated as the ratio between the average of the 24, hourly, treatment-induced BP changes and its standard deviation. RESULTS: After the initial 2-week treatment period, clinic and 24-hour ambulatory BP values were higher in non-responders (145 +/- 11/87 +/- 8 and 135 +/- 17/80 +/- 6mm Hg, respectively) than in responders (133 +/- 6/81 +/- 3 and 130 +/- 9/77 +/- 7mm Hg). In non-responders, clinic and 24-hour BP values were lowered after a further 2 weeks of treatment with ER felodipine 10 mg/day (128 +/- 11/78 +/- 6 and 128 +/- 12/75 +/- 5mm Hg). SI was high in responders (0.8 +/- 0.8/0.7 +/- 0.7 for systolic/diastolic BP) and low in non-responders (0.5 +/- 0.6/0.3 +/- 0.6) during the first 2-week treatment period. It increased in non-responders after an additional 2 weeks of treatment with ER felodipine 10 mg/day (1.0 +/- 0.8/0.7 +/- 0.6). Median T/P ratios were 0.73 and 0.61 (systolic BP and diastolic BP) in responders and 0.41 and 0.61 in non-responders after 2 weeks of treatment. At variance with SI, T/P ratios did not increase in non-responders after doubling the dosage of ER felodipine (0.34 and 0.18). ER felodipine did not increase 24-hour heart rate. A total of nine adverse events were recorded in six patients (17%), but no patients withdrew from the study. CONCLUSION: ER felodipine 5 to 10 mg/day smoothly and safely reduces 24-hour ambulatory BP in elderly patients with hypertension.