Impact of dosing time of quinapril on 24-hour hypotensive effect according to daily blood pressure profile in patients with primary hypertension

Abstract

Background Studies on chronotherapy, i.e. different dosing time in different clinical situations (eg. non-dipper patient) showed evening dosing of antihypertensive drugs, especially long-acting ACEIs, in some cases may improve or even restore normal diurnal blood pressure rythm, prevent sudden morning rise and improve morning physical exercise tolerance in hypertensive patients. The objective of the study was to assess the efficacy of morning vs. evening ACEI (quinapril) administration in dipper and non-dipper patients.
Material and methods The study included 60 patients (30 dipper and 30 non-dipper) with essential hypertension, aged 40.0 ± 15.7 years. After a week placebo run-in period patients received quinapril 10 mg. In case of ineffectiveness of treatment after 2 weeks the dose was doubled. After 4 weeks the dosing was changed into evening and then continued for the next 4 weeks. On consecutive visits office blood pressure measurement and 24-h ABPM were performed.
Results and conclusions The hypotensive effect of quinapril in office blood pressure measurements was greater and blood pressure variability (BPV) lower after the evening dosing, yet the differences observed in ABPM were not significant independently of the period of the day and the diurnal profile of BP assessed and seem to result from the difference in the antihypertensive effect only. In both dipper and non-dipper patients evening dosing of quinapril was more effective in sudden morning rise of SBP and DBP reduction. After quinapril treatment night blood pressure fall is increased independently of the dosing time. However, the day-night BP difference in nondipper patients is greater after the evening dosing. As a consequence, evening dosing of this ACEI restores normal diurnal BP rythm in higher percentage of patients.