Antihypertensive effects of clonidine.

The antihypertensive effect of clonidine given either two or three times a day with a diuretic was compared in a double-blind crossover study in 18 hypertensive patients. In 11 patients given clonidine three times a day there was better control of blood pressure, although the differences in most instances were of the order of only a few millimeters Hg. There were no differences in the frequency or severity of side effects. Clonidine twice daily with a diuretic appears to be adequate for most patients.