transdermal patches

Carvedilol is a novel, multiple-action cardiovascular drug that is currently approv-ed in many countries for the treatment of hypertension. The reduction in blood pressure produced by carvedilol results primarily from beta-adrenoceptor blockade and vasodi-lation, the latter resulting from alpha 1-adrenoceptor blockade. These actions as well as several other carvedilol activities are associated with cardioprotection in animal models that occurs to a degree that is greater than that observed with other drugs. The multiple actions of carvedilol may also provide the underlying rationale for the use of the drug in the treatment of coronary artery disease and congestive heart failure (1). Carvedilol is well absorbed from the gastrointestinal tract but is subject to consider-able first-pass metabolism in the liver; its absolute bioavailability is about 25%. It has a half-life of 2.2 ± 0.3 h; longer half-lives of about 6 h have been measured at lower con-centrations (2, 3)