Dexamethasone is absorbed rapidly after oral administration with a half-life of about 190 minutes. Sufficient absorption may occur after topical application to the skin and eye to produce systemic effects. In plasma dexamethasone protein binding is less than for most other corticosteroids. Corticosteroids diffuse into tissue fluids and cerebrospinal fluid but transplacental diffusion in significant amounts has not been demonstrated. Corticosteroids are metabilised in the liver the kidney and excrete in the urine. Metabolism is similar to other corticosteroids. Intraocular penetration occurs in significant amounts and contributes to the effectiveness of dexamethasone in anterior segment inflammatory disease.
Hormone replacement therapy (HRT) is often used to prevent osteoporosis in women. HRT does have side effects, including an increased risk of blood clots and gallbladder and heart diseases. Taking HRT as a combination therapy - estrogen with medroxyprogesterone acetate (such as Prempro) - for several years or more may increase your risk of breast cancer . All combination HRT regimens can cause patchy vaginal bleeding, particularly during the first year of use. More study is needed to learn if estrogen-only therapy increases the risk of breast cancer. The long-term benefits of HRT are, therefore, under intense study.