In this study, in hypertensive patients with a non-dipper BP pattern, a dipper BP pattern

was obtained in 64% of subjects after switching from morning to evening dosing of valsartan check details without changing its dose. Thus, this study also showed that the chronotherapeutic approach of valsartan could change a non-dipper BP pattern in hypertensive patients during morning treatment with the drug to a dipper BP pattern. SBP slightly decreased during sleep (mean, −4.1 mmHg) after switching from morning to evening dosing in the valsartan-E group. However, SBP slightly increased during waking hours (mean, +7.9 mmHg), and consequently, the dipping state was improved in this group. Dipper BP patterns were also obtained in 42–46% of patients in olmesartan-treated groups. In contrast to the valsartan-E group, SBP significantly decreased during sleep and slightly decreased during waking hours in the olmesartan-M and olmesartan-E groups. Therefore, it is likely that the influence of valsartan after evening dosing on daily BP pattern was different from those of olmesartan after morning and evening dosings under the present condition. Our previous study in SHR-SP rats showed

this website that plasma concentrations of valsartan after dosing during an inactive period were higher than those after dosing during an active period, which in turn caused the dosing time-dependent changes in the duration of unless BP-lowering effects (1). However, although plasma concentrations of olmesartan also varied with a dosing-time, the duration of BP-lowering effects were not influenced (1). Compared with valsartan, olmesartan is reported to dissociate slowly from the AII receptors of vascular tissue (14), which partially explains the chronotherapeutic differences between valsartan and olmesartan observed in the previous animal and present human studies. The chronotherapeutic

effects of olmesartan in hypertensive patients have been published, and conflicting data observed. Some research groups (18) and (19) found that, compared with morning dosing, evening dosing of olmesartan was a better dose regimen for the treatment of hypertension, whereas other research groups (20) and (21) did not support the merits of chronotherapy of olmesartan. In this study, the percent of dipper BP pattern was similar between the olmesartan-M (46%) and olmesartan-E (42%) groups, which suggests that the influence of a dosing-time of olmesartan on BP dipping state was small in hypertensive patients with a non-dipper BP pattern during valsartan treatment at morning. We do not have definitive explanations for apparent diverse findings, and further clinical studies are needed to confirm the chronotherapeutic effects of olmesartan.