A sliding intravenous dose schedule for clonidine in hypertensive patients.

Cumulative doses of clonidine were administered intravenously to 8 hypertensive patients to a maximal dose of 100 mug or a blood pressure fall to normal. There was a reduction in mean arterial pressure of 35.6 mm Hg (p less than 0.001), accompanied by a decrease in heart rate of 11.8 bpm (p less than 0.001). There was also a significant linear relationship between the reduction in blood pressure and the intravenous log dose of clonidine with 6.5-fold difference in delta MAP/dose potency. There was no correlation between the baseline blood pressure and the slopes of dose-blood pressure response curves or the reduction in mean arterial pressure; the rate of the decline of the hypotensive effect of clonidine varied widely between patients and was not related to baseline blood pressure.