Comparison of 24-hour blood pressure profiles in patients with hypertension who were switched from amlodipine to nisoldipine.

Study Objective: To compare 24-hour blood pressure control and adverse effects in patients with essential hypertension who were switched from amlodipine to nisoldipine.

Design: Open-label, one-way crossover study.

Setting: Cardiac clinic and patients' homes.

Patients: Twenty-five patients with stage I or II essential hypertension stabilized with amlodipine for at least 3 months, of whom 21 patients completed the study.

Intervention: All patients underwent 24-hour ambulatory blood pressure monitoring while receiving amlodipine 5 or 10 mg/day. Patients then were switched to nisoldipine 10 mg/day (> or = 65 yrs old) or 20 mg/day (< 65 yrs old) and returned to the clinic at 2-week intervals to assess cuff blood pressure, heart rate, adverse effects, and compliance. No adverse effects were experienced in 15 of the 25 patients. Lower extremity edema was the most commonly reported adverse effect (four patients). Two patients discontinued treatment because of pulmonary edema in one and chest pain in the other. Two patients were lost to follow-up. After a mean of 10.6 weeks, repeat 24-hour ambulatory monitoring was performed to evaluate blood pressure control with nisoldipine. Systolic and diastolic ambulatory results for daytime, nighttime, and total 24 hours were calculated. For amlodipine versus nisoldipine, no significant differences existed in any of the blood pressure parameters (p>0.05) in the 21 patients who completed the study, except for 24-hour diastolic pressure (p<0.05); however, this latter difference was only 2 mm Hg (nisoldipine 77 mm Hg, amlodipine 75 mm Hg).

Conclusion: Both amlodipine and nisoldipine have similar 24-hour ambulatory blood pressure profiles. The frequency of lower extremity edema was no different after the switch to nisoldipine than when the patients were taking amlodipine.