Transdermal hormone therapy: gels and patches.

Hormone therapy (HT) in the climacteric has a number of beneficial effects including mitigation of climacteric symptoms and prevention of osteoporosis. Administration of HT via the transdermal route avoids hepatic first-pass metabolism and therefore the high plasma levels of estrogen metabolites that are associated with oral administration. Patch formulations have traditionally been the most common form of transdermal HT. However, as patches may be associated with local skin reactions, gel formulations have been developed in an attempt to improve acceptability and compliance with transdermal HT. Patch and gel formulations are equally as effective in treating climacteric symptoms and improving bone mineral density, and the effects are comparable to those achieved by oral HT.