Hormone Replacement Therapy (menopause) - Administration and Formulations

Administration and Formulations

HRT is available in various forms. It generally provides low dosages of one or more estrogens, and often also provides either progesterone or a chemical analogue, called a progestin. Testosterone may also be included. In women who have had a hysterectomy, an estrogen is usually given without any progesterone, a therapy referred to as "unopposed estrogen therapy". HRT may be delivered to the body via patches, tablets, creams, troches, IUDs, vaginal rings, gels or, more rarely, by injection. For example, vaginally administered estrogens include those given by intravaginal tablets, creams and rings, and can have more effect on atrophic vaginitis with fewer systemic effects than estrogens delivered by other means.

Dosage is often varied cyclically to more closely mimic the ovarian hormone cycle, with estrogens taken daily and progesterone or progestins taken for about two weeks every month or two; a method called "cyclic HRT" or "sequentially combined HRT" (abbreviated scHRT). An alternate method, a constant dosage with both types of hormones taken daily, is called "continuous combined HRT" or ccHRT, and is a more recent innovation. Sometimes an androgen, generally testosterone, is added to treat diminished libido. It may also treat reduced energy and help reduce osteoporosis after menopause.

HRT is often given as a short-term relief (often one or two years, usually less than five) from menopausal symptoms (hot flushes, irregular menstruation, fat redistribution, etc.). Younger women with premature ovarian failure or surgical menopause may use hormone replacement therapy for many years, until the age that natural menopause would be expected to occur.

Formulations of estradiol include:

• Oral tablets, commonly given in amounts of 1 to 2 milligrams of estradiol per day.
• Estrogen patches
• Estrogen transdermal gels

In addition, there are many formulations of estradiol combined with one of various progestins, such as norethisterone (in Activelle), levonorgestrel, medroxyprogesterone (in Indivina), dienogest or drospirenone.