Usefulness of transdermal clonidine in hypertensive patients undergoing minor surgical operations

Transdermal clonidine (TTSC) treatment was evaluated in 29 patients with mild to moderate hypertension scheduled for minor surgery. Two weeks before the scheduled operation, patients underwent 24-h ambulatory blood-pressure monitoring (ABPM) to evaluate the efficacy of previous oral antihypertensive treatment, which was then substituted with TTSC, 0.1 mg/day. After 1 week, the efficacy of TTSC was clinically assessed, and the dose increased to 0.2 mg/day if needed. ABPM was repeated 2 days before the scheduled operation and 2 days after surgery. The 24-h blood pressure (BP) and heart rate (HR) profiles were smoothed by Fourier analysis. Three patients withdrew for adverse events and one for inefficacy after dose adjustment, TTSC being effective in the remaining 25 patients. Two patients who completed treatment lacked postsurgical ABPM recording. In the 23 patients with all ABPM recordings, average 24-h BP and HR obtained preoperatively during TTSC treatment were slightly reduced compared with values recorded during previous oral therapy. BP changes after surgery were negligible, whereas HR showed a moderate increase. Minor adverse events occurred in four (14%) of 29 patients. Our results demonstrate that TTSC provides adequate BP control in patients with mild to moderate hypertension undergoing minor surgery.