Botulinum Toxin for Pelvic Pain in Women With Endometriosis

Chronic pelvic pain associated with endometriosis is poorly understood. Some women with chronic pelvic pain have muscle spasm of their pelvic muscles. Muscle spasm may be a significant part of pain in women with endometriosis and other types of chronic pelvic pain. Botulinum toxin injection is widely used to treat conditions associated with excessive muscle activity and spasm. Studies of botulinum toxin injected into pelvic muscles of women with pelvic pain have shown a decrease pain and spasm, but too few women have been studied to conclude its effectiveness. We expect to show that botulinum toxin injection in women with pelvic pain will relieve some of their pelvic pain.

Eligible subjects will be otherwise healthy women who have chronic pelvic pain and a history of endometriosis. Subjects will be randomized to either botulinum toxin injection or placebo (salt water) injection. After one month, we will evaluate the presence of the pain and all women will be offered botulinum toxin injection. We will also evaluate the need for reinjection.

• INCLUSION CRITERIA:
• Female gender
• Age between 18 and 55
• History of endometriosis at surgery
• Persistent pelvic pain for at least 3 months
• Pelvic floor spasm
• Negative pregnancy test (in women who have not had a hysterectomy)
• Willing to use reliable method of contraception for the month after botulinum toxin injection including oral contraceptives, IUD, and barrier with spermicide.
• Willing and able to give informed consent
• Willing and able to comply with study requirements

Exclusion criteria

• Women with other causes of chronic pelvic pain including infectious, gastrointestinal, psychological disorders, fibromyalgia and chronic fatigue syndrome based on review of medical history within 1 year of first study visit,
• Untreated severe cervical dysplasia or other gynecologic condition clinically significant abnormalities on physical or laboratory examinations that require evaluation or treatment or that would make participation unsafe
• Hysterectomy and bilateral salpingo-oophorectomy
• Pregnancy
• Lactation
• Allergy to albumen or botulinum toxin
• Presence of antibodies to botulinum toxin or loss of response to previous injections for any indication
• A known neuromuscular junction disorder such as myasthenia gravis or Eaton-Lambert syndrome
• History of urinary or fecal incontinence
• Known pelvic prolapse

• Eligibility will be based on a physical exam at NIH at the first study visit, as well as history and available medical records within 1 year before the study visit. Negative test results will be documented to confirm study eligibility. If the Pap and the GC and chlamydia tests were not done outside of the NIH within the previous year, or if documentation of the negative test results is not available, we will await the results of the screening tests done at the NIH before administering the study medication.