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OCs eyed for relief of endometriosis pain
Endometriosis is a common gynecologic disorders; about 3%-10% of American reproductive-age women have endometriosis.1 Dysmenorrhea is the most common symptom reported by patients with endometriosis. What is your approach when it comes to treatment of such pain?
Research published in November 2008 assesses the use of oral contraceptives (OCs) in treating pain associated with endometriosis.2 In a double-blind, randomized, placebo-controlled trial, scientists assessed the outcomes of 100 women who used a combined oral contraceptive (0.035 mg ethinyl estradiol plus 1 mg norethisterone) or placebo. Women who used the Pill took active pills for 21 days plus seven days of placebo, while the control group used placebo pills for 28 days. Women were treated for four cycles, with a verbal rating scale and a visual analog scale used to assess dysmenorrhea-related disability and analgesic use.
Total dysmenorrhea scores significantly decreased at the end of treatment in the OC and placebo groups; however, the reduction in pain score was significantly higher in the OCP group2 compared with the placebo group (0.6) (P < 0.0001). Women who used OCs also reduced the number of days analgesics were used, researchers note.2
Use careful evaluation
Pain associated with endometriosis requires careful evaluation to exclude other potential causes, advises a new practice committee report issued by the American Society for Reproductive Medicine in Birmingham.3 Medical and surgical treatments for pain related to endometriosis are effective, and choice of treatment must be individualized, the report states.
Other conditions of the reproductive tract can cause chronic pelvic pain, such as adenomysosis, pelvic adhesions, pelvic inflammatory disease, congenital anomalies of the reproductive tract, and ovarian or tubal masses. Conditions such as irritable bowel syndrome, interstitial cystitis, and fibromyalgia also can lead to pelvic pain. A thorough evaluation to exclude other causes of pelvic pain should be pursued prior to aggressive therapy for endometriosis, the report advises.3
Oral contraceptives can be a valuable adjunct to the treatment options used by clinicians for the pelvic pain caused by endometriosis, says David Adamson, MD, director of Fertility Physicians of Northern California in San Jose. An adjunct clinical professor at Stanford University and associate clinical professor at the University of California San Francisco, Adamson is past president of the American Society for Reproductive Medicine and a founding board member of the World Endometriosis Research Foundation in London. Since OCs are relatively safe, well tolerated, and inexpensive in comparison with other treatment modalities, they are often a first-line defense against pain experienced by those with endometriosis, he states.
Check GnRH agonists
Gonadotrophin-releasing hormone (GnRH) agonists, such as leuprolide acetate and nafarelin acetate, are modified forms of GnRH that bind to receptors in the pituitary. They serve to induce amenorrhea and progressive endometrial atrophy. While often used in medical management of endometriosis, side effects can include hot flushes, vaginal dryness, emotional lability, and loss of libido.2 Use of these drugs has been linked to loss in bone mineral density, which might not be reversed until a few years after completion of treatments.4
Some patients respond better to use of leuprolide acetate, says Adamson. Due to potential bone issues, use of the drug is generally recommended for six months. Research indicates that GnRH agonist and norethindrone acetate, alone or combined with low-dose conjugated equine estrogens, administered to symptomatic endometriosis patients for 12 months provided extended pain relief and bone mineral density preservation after completion of therapy.5
A 2007 Cochrane Database of Systematic Reviews, which looked at all studies regarding the use of OCs for pain associated with endometriosis from 1966-2006, noted one randomized clinical trial that met its inclusion criteria.6 That trial, which looked at use of a low-dose OC vs. goserelin, a GnRH agonist, found no evidence of a significant difference between the groups with regard to reduction in recurrence of dysmenorrhea at the end of its six-month follow-up period.7
What are other options?
Research also is looking into other hormonal options when it comes to treating pain associated with endometriosis. One small trial looked at patients with dysmenorrhea, nonmenstrual pelvic pain, and dyspareunia associated with histologically proven endometriosis using the contraceptive implant Implanon or the contraceptive injection depot medroxyprogesterone acetate (DMPA). Researchers report that after six months, the average decrease in pain was 68% in the Implanon group and 53% in the DMPA group.8 In the research examining OC use, the visual analog scale score for dysmenorrhea fell from 58.7 to 27.6 in the OC group, and from 55.8 to 46.2 in the placebo group.2
Scientists also have considered use of the levonorgestrel intrauterine system (LNG-IUS) for treatment of endometriosis-related pain. Results of a 2005 study, which looked at use of the LNG-IUS and a GnRH analogue, indicate both were effective in the treatment of chronic pelvic pain-associated endometriosis, although no differences were observed between the two treatments.9