Oral clonidine loading for rapid control of hypertension.

In order to determine the efficacy and safety of oral clonidine loading to control hypertension rapidly, 15 patients received 0.1 or 0.2 mg clonidine initially followed by hourly doses of 0.1 mg until the blood pressure was substantially reduced or until a total of 0.5 mg had been given. Twelve (80%) responded with a reduction in mean blood pressure of 33 +/- 3 (SE) mm Hg in an average time of 2.25 hr. Side effects were minimal. Four of the 5 patients hospitalized solely for purposes of blood pressure control responded to clonidine loading and were discharged the next day. Clonidine loading proved to be safe and effective for rapid control of hypertension and may be preferred to intravenous antihypertensives for some indications.