What Medications Are Used for the Treatment Endometriosis and Pelvic Pain?
Managing pain caused by endometriosis is the cornerstone of successful treatment because pain is the most common reason women with endometriosis go to the doctor.
- To halt or slow the progression of endometriosis, the doctor will start by prescribing medication. Surgery is recommended only if medications fail, unless there is severe or advanced disease or a suspicion of cancer.
- The primary therapy initially recommended for the pain of endometriosis is a nonsteroidal antiinflammatory drug (NSAID) such as ibuprofen (Motrin or Advil) or naproxen sodium (Aleve).
- If NSAIDs are not sufficient for pain control, the doctor may prescribe stronger medications, even including opioid (narcotic) drugs. Care should be taken when using these drugs due to the possibility for abuse, addiction, and withdrawal symptoms.
- Depending on the severity of the disease, the next step in the treatment of endometriosis is to slow or halt the proliferation of the endometrial tissue outside of the uterus. Different treatment strategies may be employed to change the hormone levels that promote endometriosis.
Gonadotropin-releasing hormone analogs (GnRH analogs)
Gonadotropin-releasing hormone agonists and antagonists may be prescribed to relieve pain and reduce the size of endometriosis implants. These drugs may be administered by nasal spray, by intramuscular injections, or by the newer oral preparation elagolix (Orilissa), which was approved by the US FDA in in 2018. All of these medications drugs suppress estrogen production by the ovaries, resulting in a cessation of menstrual periods, and signs and symptoms mimicking those of the menopausal transition including:
Fortunately, many of the annoying side effects due to estrogen deficiency can be avoided by administering estrogen in pill form (called "add back" therapy).
Oral Contraceptive Pills (Birth Control Pills)
Oral contraceptive pills (OCPs, estrogen, and progesterone in combination, birth control pills) are occasionally used to treat endometriosis in women who also desire contraception. Side effects of oral birth control pills include:
Progestins [for example, medroxyprogesterone acetate (Provera), norethindrone acetate (Aygestin, Camila, Errin, Jolivette, Nor-QD, Nora-Be, Ortho Micronor), norgestrel acetate (Ovrette)] are sometimes used in women who do not obtain pain relief from OCPs. Side effects of progestins include:
Danazol (Danocrine) is a synthetic drug that stimulates high levels of androgens (male type hormones) and low estrogen levels by interfering with ovulation and ovarian production of estrogen. This drug is effective for pain relief and shrinkage of endometriosis implants, but has a high incidence of side effects including:
- Weight gain
- Decrease in breast size
- Oily skin
- Male pattern hair growth (hirsutism)
- Deepening of the voice
- Hot flashes
- Changes in sex drive (libido)
- Mood changes
All of these changes except for voice changes are reversible, but the return to normal may take many months. Women with certain types of liver, kidney, and heart conditions should not take danazol.
Another strategy to treat encometriosis is with drugs known as aromatase inhibitors, for example, anastrozole (Arimidex) and letrozole (Femara). Aromataste inhibitors disrupt estrogen formation within the endometriosis implants themselves. They also inhibit estrogen production in other areas of the body. Aromatase inhibitors cause significant bone loss with prolonged use. A further drawback is that these drugs stimulate development of multiple follicles at ovulation so they must be used with caution in premenopausal women and may be combined with another medications such as GnRH agonists or birth contol pills to suppress the development of follicles.