There is a dilemma and a permanent debate about side effects on drugs administered orally.
The first-pass metabolism is related with many side effects, since the metabolites of these
compounds affect the course of human physiology. Conventional hormone therapy by oral route
has been used for relieving menopausal symptoms. Transdermal estrogens have not been used
extensively in Brazilian women with menopausal symptomatology, however; recently a previous
long term study has indicated no increased risk breast cancer or vasomotor disorders in
menopausal women, using transdermal HRT.