The USA experience with the clonidine transdermal therapeutic system.

Cardiovascular diseases are the leading causes of death in the United States, with hypertension being amongst the most prevalent of the cardiovascular risk factors. Improvement of hypertension management has, in consequence, received much attention. Extensive pre- and post-marketing experience with the transdermal formulation of clonidine marketed in the USA in the mid-1980s has now been accumulated. Transdermal clonidine is effective as monotherapy in mild-moderate hypertension, and in combination with diuretics, calcium antagonists and ACE inhibitors in more resistant cases. It controls blood pressure throughout the 24-h circadian cycle. It is effective and generally well-tolerated in adolescents, the elderly, blacks, diabetics, and subjects with chronic renal insufficiency. It has been used perioperatively and for suppression of adrenergic symptoms in subjects withdrawing from addicting substances. In comparison with oral clonidine, transdermal clonidine reduces the incidence and severity of such symptomatic side-effects as dry mouth, drowsiness, and sexual dysfunction. Minor skin reactions occur at the site of application of the transdermal patch with moderate frequency. Adherence to transdermal clonidine therapy is high, and patients commonly prefer it to oral therapy. Transdermal administration of clonidine is a useful therapeutic advance in the long-term management of hypertension.