The literature is reviewed for contact dermatitis associated with transdermal therapeutic systems. Clonidine, nitroglycerin, scopolamine, estradiol and testosterone are utilized in such applications, and fentanyl is under investigation. Most cutaneous reactions are limited to localized dermatitis; however, generalized systemic effects may occur. Investigators are reporting skin-related side-effects in up to 50% of patients using transdermal clonidine; however, with the other agents, this is demonstrated much less frequently. Reactivation of the dermatitis via oral medication, following sensitization to the patch, is noted in rare instances.Key words: transdermal therapeutic systems; contact dermatitis; adverse cutaneous reactions; donidine; nitroglycerin; scopolamine; estradiol; testosterone; fentanyl.
Accepted fur publication 20 August 1988Transdermal therapeutic systems (TTS) have made possible effective "rate-controlled" transcutaneous administration of certain drugs. A number of other advantages include elimination of gastrointestional absorption, reduced total dosage, less expense than intramuscular or intravenous administration where applicable, avoidance of "first-pass" inactivation by the liver, use of agents with a narrow therapeutic index, and improved compliance with decreased administration cycle. Although these devices have proven quite useful, they are not without side-effects. One limitation is that of contact dermatitis, which in some instances necessitates discontinuation of the patch. It is the intention of this article to review the local and systemic side-effects of these systems.5 TTS are commercially available, which contain the compounds clonidine, nitroglycerin, scopolamine, estradiol, and testosterone; fentanyl is currently under investigation. Each consists basically of 4 membranes, as demonstrated in Fig. 1. The reservoir is surrounded by an occlusive backing membrane, which prevents the outward diffusion of the drug. A control microporous membrane allows diffusion of the medication at a constant controlled rate into the skin, with an adhesive for attachment to the surface. The approximate thickness of the 4 membranes is 0.2 mm.
Adverse ReactionsClonidine is a centrally acting alpha-agonist used primarily as an antihypertensive agent. Standard predictive tests in guinea pigs indicate that it is not a contact allergen, as confirmed by clinical trials with the oral form (1). However, when the transdermal patch became available, a larger than expected proportion of users became sensitized. The most commonly reported side-effects of dry mouth and drowsiness were generally decreased with transdermal therapy (2, 3). Rebound hypertension with the patch has only rarely been reported (4, 5).