title: Clonidine twice daily in hypertension. Effects of two dosage regimens on blood pressure, side-effects and plasma clonidine concentrations.
abstract: The effects of two b.i.d. dosing schedules of clonidine on blood pressure, side-effects and plasma concentration of clonidine were studied in a randomized cross-over study. The blood pressures of 10 hypertensive inpatients on diuretic treatment were recorded every 3-4 hours throughout the study. A twice-daily regimen with 0.075 mg clonidine administered at 8 a.m. and 0.15 mg at 10 p.m. resulted in a wider fluctuation of blood pressure than the same doses given at 8 a.m. and 4 p.m. The most conspicuous finding was the significant rise (p less than 0.001) of diastolic blood pressure at 8 p.m., when clonidine was given at 8 a.m. and 10 p.m. The overall mean values of supine systolic and diastolic blood pressures were normotensive and did not differ from each other in the two dosing schedules. There were no obvious differences in subjective side-effects between the two regimens. Predose clonidine concentrations varied interindividually between 0.15 and 1.12 ng/ml, but the fluctuation in one and the same subject was small and related to dose and its timing. Thus, twice-daily dosing of clonidine seems to result in a satisfactory blood pressure reduction. Fluctuation of blood pressure is greater when the evening dose is given at 10 p.m.
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D002986:Clinical Trials as Topic; D003000:Clonidine / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood; D004334:Drug Administration Schedule; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D011897:Random Allocation
chemical_list: D003000:Clonidine