Oral substitution in patients sensitized by transdermal clonidine treatment.

The safety of oral clonidine substitution in 29 patients with confirmed localized allergic contact dermatitis due to transdermal clonidine treatment was evaluated. Only 1 patient had a skin reaction to oral clonidine. The dose of topical clonidine-inducing sensitization, and the oral challenge dose administered later, appear to be insufficient to elicit a systemic reaction in most patients. An examination of current patch test technology seems indicated in view of the fact that a number of patients who gave a negative reaction to 48-h applications of 9% clonidine in petrolatum responded positively to 7-day application of transdermal clonidine.