Hypertensive emergencies treated with oral clonidine.

Thirty-eight severely hypertensive patients were treated with oral clonidine. Each patient received a "loading" dose of 0.2 mg clonidine, followed by 0.1 mg hourly until the blood pressure was substantially reduced, or until a total dose of 0.8 mg has been administered. Thirty-five (82.1%) patients responded favourably, with a reduction in the systolic blood pressure in the supine position from 210 +/- 20 to 145 +/- 20 and to 98 +/- 15 mmHg diastolic after 6 hours. The average dose of clonidine was 0.5 mg. Side-effects were minimal. The study has shown that oral clonidine given in a "loading" dose is safe and effective in the management of patients with hypertensive emergencies, and it may have an advantage over other antihypertensive drugs administered parenterally.