Abstract: AIM: To investigate the effect of bisoprolol with different time on blood pressure control and circadian variability of dipper blood pressure for patients with non-dipper hypertension.METHODS: The patients were randomly divided into two parallel groups. All patients were treated with bisoprolol. The first group took bisoprolol at eight o'clock once-daily between 2.5 mg and 10 mg. The second group took bisoprolol at twenty o'clock once-daily between 2.5 mg and 10 mg. The efficiency of the 8 weeks' treatment and the change of the 24 hours blood pressure were detected.RESULTS: Thebloodpressuresof thepatientsinbothgroups were decreased(P<0.05). And there was no significant difference between the two groups for the day BP decrease (P>0.05), but taking bisoprolol at first group had a better efficacy than that in the second group of the ninght BP. On the recovery diurnal rhythm of blood pressure the first group was better than that of second group (P<0.05). There were 10 hypertensive patients with non-dipper pattern of blood pressure changed into dipper pattern in the first group while there were 19 patients changed in the second group.CONCLUSION: Two methods of treatment can control the blood pressure safe and efficacy, but taking drug at eight o'clock is better for the non-dippers hypertension and the diurnal rhythm of blood pressure than taking at twenty o'clock.

Key words: Bisoprolol, Non-dippers hypertension, Dippers hypertension, Diurnal rhythm of blood pressure