Captopril administered at night restores the diurnal blood pessure rhythm in adequately controlled, nondipping hypertensives

The aim of our study was to evaluate whether captopril administered at night, can shift the circadian blood pressure (BP) from a nondipper to a dipper pattern in adequately controlled hypertensive patients, who continued their antihypertensive therapy. In a prospective, randomized, double blind, placebo-controlled designed study, we enrolled 121 treated, adequately controlled nondipping hypertensive patients. All patients were randomly assigned to 12.5 mg captopril or placebo treatment administered at night. In case of nondippers, the dosage of captopril or placebo was doubled after two weeks of treatment, while for dippers antihypertensive regimens were not changed. After another two weeks, all patients underwent ambulatory BP monitoring. Our results show that at the end of the active treatment period, the prevalence of a dipping diurnal BP pattern in the captopril group (70%) was significantly higher than that in the placebo group (9.8%, P < 0.001). Nighttime BP, night/day BP ratio, nighttime BP load and 24-h systolic BP were significantly lower after 4 weeks nighttime captopril treatment compared to baseline. In conclusion, the present study demonstrates for the first time that captopril administered at night can restore the diurnal BP rhythm and decrease the elevated night/day BP ratio in appropriately controlled, nondipper hypertensive patients. These results were mainly due to the decrease of nighttime BP.