The effectiveness and safety of transdermally administered clonidine hydrochloride was assessed in 16 patients with type-II diabetes mellitus. This group of patients was chosen because of the frequent occurrence of hypertension in diabetic patients and potential problems with transdermal absorption of medication because of small vessel disease. A skin patch containing clonidine hydrochloride (Catapres TTS) was applied at weekly intervals after an appropriate placebo lead-in period. Satisfactory response to therapy was seen in 15 of the 16 patients. One patient developed a generalized skin rash and was withdrawn from the study. Correlation between change in diastolic blood pressure and plasma clonidine levels was noted. Of note was the absence of the usual side effects (drowsiness, dry mouth, etc.) seen with oral clonidine administration. This study thus highlights the success of transdermal clonidine therapy in controlling blood pressure in the mild hypertensive patient with diabetes mellitus.
