Add-back therapy and gonadotropin-releasing hormone agonists in the treatment of patients with endometriosis: can a consensus be reached? Add-Back Consensus Working Group.

OBJECTIVE: To reach a consensus on the role of add-back therapy for patients with endometriosis administered GnRH agonists (GnRH-a).

DESIGN: Results of consensus conference reviewing MEDLINE search of English language abstracts of both prospective and retrospective series.

SETTING: Consensus conference of 31 specialists in gynecologic surgery and reproductive endocrinology.

PATIENT(S): Patients with symptomatic endometriosis who were candidates for GnRH-a therapy in treatment courses ranging in duration from 6 to 12 months.

INTERVENTION(S): Oral steroidal and nonsteroidal add-back regimens.

MAIN OUTCOME MEASURE(S): Alteration in painful symptoms, extent of disease, vasomotor symptoms, bone mineral density, and serum lipid profile.

RESULT(S): When added to GnRH-a for 6 months, both 2.5 mg of norethindrone and 0.625 mg of conjugated equine estrogens with 5 mg/d of medroxyprogesterone acetate provide effective relief of vasomotor symptoms and decrease but do not eliminate bone mineral density loss. During 12 months of GnRH-a therapy, bone mineral density loss is eliminated effectively with an add-back of 5 mg of norethindrone acetate alone or in conjunction with low-dose conjugated equine estrogens. Organic bisphosphonates also may play a role.

CONCLUSION(S): In patients with symptomatic endometriosis, the efficacy of GnRH agonists may be preserved and therapy prolonged while overcoming hypoestrogenic side effects with the use of appropriate add-back regimens.