The newly developed calcium antagonist, azelnidipine, increases drain volume in continuous ambulatory peritoneal dialysis patients.

Many patients undergoing continuous ambulatory peritoneal dialysis (CAPD) receive antihypertensive agents, including calcium antagonists, which produce reflex tachycardia through activation of the sympathetic nervous system. Azelnidipine, a newly developed calcium antagonist, has unique characteristics in that it causes less reflex stimulation of the sympathetic nervous system. In the present study, we used a crossover method to compare the effects of amlodipine (5-10 mg daily) and azelnidipine (8-16 mg daily) on drain volume and weekly creatinine clearance in 9 CAPD patients (3 women, 6 men; mean age: 64 +/- 5 years; mean duration of CAPD: 1.8 +/- 0.6 years). Each calcium antagonist was administered for 3 months and then switched for the other. As compared with amlodipine, azelnidipine increased drain volume by 13% +/- 2% (p < 0.05) and weekly creatinine clearance by 12% +/- 2% (p < 0.05). At the same time, we observed no significant differences in blood pressure and urine volume. The increases in drain volume produced by azelnidipine resulted from less activation of the sympathetic nervous system. We therefore suggest that activation of the sympathetic nervous system induced by calcium antagonists may be important in the regulation of drain volume in CAPD patients.