Rapid reduction of severe asymptomatic hypertension with orally administered antihypertensive medication has become a common emergency department practice. To determine if antihypertensive loading prior to initiation of maintenance therapy improved or hastened blood pressure control, 64 asymptomatic patients with severe hypertension were randomized to treatment with (1) hourly doses of clonidine hydrochloride followed by maintenance therapy (group 1); (2) an initial dose of clonidine followed by hourly placebo and subsequent maintenance therapy (group 2); or (3) maintenance therapy without prior loading (group 3). There was no difference between groups 1 and 2 in the time required to achieve acceptable blood pressure control during loading therapy, nor was there a difference at 24 hours in pressure reduction between groups 1,2, or 3. Further follow-up in 44 of these patients at 1 week demonstrated adequate control of systemic blood pressure in all groups, but no difference between groups. In view of the small but reported risk of antihypertensive loading and the burden and expense of prolonged emergency department therapy, these results suggest that the common practice of acute oral antihypertensive loading to treat severe, asymptomatic hypertension should be reconsidered.