What medications treat endometriosis?
Nonsteroidal anti-inflammatory drugs (NSAIDs)
Nonsteroidal anti-inflammatory drugs or NSAIDs (such as ibuprofen or naproxen sodium) are commonly prescribed to help relieve pelvic pain and menstrual cramping. These pain-relieving medications have no effect on the endometrial implants or the progression of endometriosis. However, they do decrease prostaglandin production, and prostaglandins are well-known to have a role in the causation of pain. As the diagnosis of endometriosis can only be definitively confirmed with a biopsy, many women with complaints suspected to arise from endometriosis are treated for pain first without a firm diagnosis being established. Under such circumstances, NSAIDs are commonly used as a first line empirical treatment. If they are effective in controlling the pain, no other procedures or medical treatments are needed. If they are ineffective, additional evaluation and treatment will be necessary.
Since endometriosis occurs during the reproductive years, many of the available medical treatments for endometriosis rely on interruption of the normal cyclical hormone production by the ovaries. These medications include GnRH analogs, oral contraceptive pills, and progestins.
Gonadotropin-releasing hormone analogs (GnRH analogs)
Gonadotropin-releasing hormone analogs (GnRH analogs) have been effectively used to relieve pain and reduce the size of endometriosis implants. These drugs suppress estrogen production by the ovaries by inhibiting the secretion of regulatory hormones from the pituitary gland. As a result, menstrual periods stop, mimicking menopause. Nasal and injection forms of GnRH agonists are available.
The side effects are a result of the lack of estrogen, and include:
Fortunately, by adding back small amounts of progesterone in pill form (similar to treatments sometimes used for symptom relief in menopause), many of the annoying side effects due to estrogen deficiency can be avoided. "Add back therapy" is a term that refers to this modern way of administering GnRH agonists along with progesterone in a way to ensure compliance by eliminating most of the unwanted side effects of GnRH therapy.
Oral contraceptive pills
Oral contraceptive pills (estrogen and progesterone in combination) are also sometimes used to treat endometriosis. The most common combination used is in the form of the oral contraceptive pill (OCP). Sometimes women who have severe menstrual pain are asked to take the OCP continuously, meaning skipping the placebo (hormonally inert) portion of the cycle. Continuous use in this manner will generally stop menstruation altogether. Occasionally, weight gain, breast tenderness, nausea, and irregular bleeding may occur. Oral contraceptive pills are usually well-tolerated in women with endometriosis.
Progestins [for example, medroxyprogesterone acetate (Provera, Cycrin, Amen), norethindrone acetate, norgestrel acetate (Ovrette)] are more potent than birth control pills and are recommended for women who do not obtain pain relief from or cannot take a birth control pill. They may be helpful in women who do not respond, or cannot take (for medical reasons) oral contraceptives.
Side effects are more common and include:
Because the absence of menstruation (amenorrhea) induced by high doses of progestins can last many months following cessation of therapy, these drugs are not recommended for women planning pregnancy immediately following cessation of therapy.
Other drugs used to treat endometriosis
Danazol (Danocrine) is a synthetic drug that creates a high androgen (male type hormone) and low estrogen hormonal environment by interfering with ovulation and ovarian production of estrogen. Eighty percent of women who take this drug will have pain relief and shrinkage of endometriosis implants, but up to 75% of women develop significant side effects from the drug. These include:
- weight gain,
- edema (swelling),
- breast shrinkage,
- oily skin,
- hirsutism (male pattern hair growth),
- deepening of the voice,
- hot flashes,
- changes in libido, and
- mood alterations.
Except for the voice changes, all of these side effects are reversible. In some cases, resolution of the side effects may take many months. Danazol should not be taken by women with certain types of liver, kidney, or heart conditions. This product is rarely used.
A more current approach to the treatment of endometriosis has involved the administration of drugs known as aromatase inhibitors (for example, anastrozole [Arimidex] and letrozole [Femara]). These drugs act by interrupting local estrogen formation within the endometriosis implants themselves. They also inhibit estrogen production within the ovary and adipose tissue. Research is ongoing to evaluate the effectiveness of aromatase inhibitors in the management of endometriosis. Aromatase inhibitors can cause significant bone loss with prolonged usage. They must also be employed in combination with other drugs in premenopausal women because of their effects on the ovaries.