Endometriosis - Medications

Side Effects of Progestins. Side effects of progestin occur in both the combination oral contraceptives and any contraceptive that only uses progestin, although they may be less or more severe depending on the form and dosage of the contraceptive. Side effects may include the following:

Changes in uterine bleeding. Such as higher amounts during periods, spotting and bleeding between periods (called break-through bleeding), or absence of periods. Be sure to check with the physician if any of these occur.
Unexpected flow of breast milk. (Check with the physician if this occurs to be sure other abnormalities are not causing it.)
Abdominal pain or cramps.
Diarrhea.
Fatigue, unusual tiredness, weakness.
Hot flashes.
Decreased sex drive.
Nausea.
Trouble sleeping.
Acne or skin rash. (Low-dose OCs actually improve acne. Only Ortho Tri-Cyclen is approved for this.)
Depression, irritability, or other mood changes.
Swelling in the face, ankles, or feet.
Weight gain.

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Newer formulations of combination pills that use low-dose estrogen and newer progestins may reduce and even avoid many of these side effects. Progestins used in non-oral contraceptives, such as the LNG-IUS IUD, also may not pose as high a risk for these side effects. If side effects persist or are severe, a woman should always talk to her physician. Many women do not experience these side effects, or if they do, their bodies eventually adjust.

GnRH Agonists

Gonadotropin releasing hormone (GnRH) agonists are effective hormone treatments for endometriosis. They are able to block the release of the reproductive hormones LH (luteinizing hormone) and FSH (follicular-stimulating hormone). As a result, the ovaries stop ovulating and no longer produce estrogen.

Specific GnRH Agonists. GnRH agonists include goserelin (Zoladex), buserelin, a monthly injection of leuprolide (depot Lupron), and a nasal spray, Nafarelin (Synarel). Studies have reported that nafarelin shrank all implants and significantly relieved symptoms in 85% of patients, delayed recurrence of endometriosis after surgery, and in comparison with leuprolide, was less expensive, had fewer side effects, and a provided better quality of life.

Side Effects and Complications. Commonly reported side effects (which can be severe in some women) include menopause-like symptoms that include hot flashes, night sweat, and changes in the vagina, weight change, and depression. The side effects vary in intensity depending on the GnRH agonist. They may be more intense with leuprolide and persist after the drug has been stopped.