Time-dependent effect of isradipine on the nocturnal hypertension in chronic renal failure.

Nocturnal hypertension is frequently observed in chronic renal failure and contributes to the risk of target organ damages. We assessed whether antihypertensive therapy may restore a nocturnal blood pressure (BP) fall in this condition. A sustained-release oral formulation (SRO) of isradipine was used, and the possible differences in the response to morning nu evening dosing were also investigated. Sixteen hypertensive patients with chronic renal failure due to parenchymal kidney disease were studied after 2 weeks of single-blind placebo runin. According to the double-blind, randomized, cross-over design, they received 5 mg isradipine SRO at 08:00, or at 20:00 for 4 weeks, separated by a single-blind placebo period of 2 weeks. A 24-h BP monitoring at 10-min intervals was carried out at the end of each treatment using a SpaceLabs 90207 instrument. Under placebo, blunt BP profiles were observed, whereas HR showed a mean nocturnal fall of 17.4%, which remained unaltered after isradipine. Both isradipine treatments were equally effective in reducing the mean 24-h BP levels. However, the evening regimen showed a more pronounced effect during the night. The mean nocturnal fall in systolic/diastolic BP represented 4.8/8.7% and 7.5/10.9% of the corresponding daytime mean after morning and evening dosing, respectively. Only the evening administration reset the normal synchronization of the 24-h BP and HR profiles. Our findings demonstrate that antihypertensive treatment may restore a nocturnal BP fall in renal patients. An evening regimen of isradipine SRO seems more apt than a morning regimen to obtain this therapeutic goal.