A clinical study on the prolonged antihypertensive effect of clonidine in a sustained-release capsule formulation.

Eight patients with essential hypertension each received a single oral dose of 1 capsule of a sustained-release formulation of 0.25 mg clonidine in the morning for 3 consecutive days. Pulse ratio and blood pressure were measured in the standing and supine positions at specific intervals. After the first day of treatment, a significant decrease in blood pressure lasting 24 hours was recorded for the standing position. In the supine position, there was a progressive decrease in blood pressure which also attained significance on the third day of treatment. There was a progressive and significant reduction in mean arterial pressure from the first to the third day.