The following are the commonly prescribed hormone replacement therapy (HRT) medications:
Forms of HRT/ ERT (estrogen replacement therapy): Hormones are available in several forms. All are effective in treating hot flashes, and certain formulations cause fewer side effects than others. Estrogen is available as a pill (taken orally) or as a patch (applied to the skin). Progesterone is available as a pill or as a vaginal suppository. For women taking estrogen and progesterone, combined pills and patches also are available.
- Premarin is the most commonly prescribed estrogen in the U.S. The estrogen patch is less likely than oral forms of the hormone to cause headache and nausea or to promote the formation of gallstones.
- Provera is the most commonly prescribed progesterone. Progesterone is also available as a vaginal suppository, which may be less likely to cause progesterone-related side effects such as breast tenderness, irritability, depression, and headaches.
Estrogen versus estrogen-progesterone combinations: Women who have not had a hysterectomy need to take progesterone in combination with estrogen to protect against uterine cancer.
Continuous versus cyclic therapy: For women who have not had a hysterectomy, the traditional way of prescribing HRT simulates the normal monthly cycling of hormones in the body. A woman on cyclic therapy receives estrogen alone for about 15 days, then estrogen plus progesterone for 10 days, and then nothing for 5 days each month. This usually results in regular menstrual bleeding six or more days after starting the progesterone-containing agent. Bleeding can be moderately heavy at first, but periods usually become light within six months.
An alternative method of taking HRT is to take estrogen and low-dose progesterone every day. Women who choose this regimen will generally not experience regular menstrual periods but will often have irregular, light spotting.
Women who have only recently entered menopause are likely to experience excessive, unpredictable bleeding if they take a continuous regimen. Therefore, women whose periods have stopped within the past six months may benefit from a cyclic regimen for six to twelve months.