Long-Term Effects of Gonadotropin-Releasing Hormone Agonists and Add-Back in Adolescent Endometriosis.

Study Objective: To explore the potential occurrence of long-term side effects and tolerability of gonadotropin-releasing hormone agonist (GnRHa) plus 2 different add-back regimens in adolescent patients with endometriosis.

Design: Follow-up questionnaire sent in 2016 to patients who participated in a drug trial between 2008 and 2012.

Setting: Tertiary care center in Boston, Massachusetts.

Participants: Female adolescents with surgically confirmed endometriosis (n = 51) who enrolled in a GnRHa plus add-back trial as adolescents.

Interventions: Leuprolide depot 11.25 mg intramuscular injection every 3 months, plus oral norethindrone acetate 5 mg daily or oral norethindrone acetate 5 mg daily and oral conjugated equine estrogens 0.625 mg daily.

Main Outcome Measures: Side effects during and after treatment, irreversible side effects, changes in pain, overall satisfaction.

Results: The response rate was 61% (25 of 41; 10 subjects could not be located). Almost all (24 of 25) reported side effects during treatment; 80% (16 of 21) reported side effects lasting longer than 6 months after stopping treatment. Almost half (9 of 20) reported side effects they considered irreversible, including memory loss, insomnia, and hot flashes. Despite side effects, participants rated GnRHa plus add-back as the most effective hormonal medication for treating endometriosis pain; two-thirds (16 of 25) would recommend it to others. More participants who received a modified 2-drug add-back regimen vs standard 1-drug add-back would recommend GnRHa and believed it was the most effective hormonal medication.

Conclusion: Subjects believed that GnRHa used with add-back was effective and would recommend it to others, despite significant side effects. Those who received 2-drug add-back reported more success than those who received standard add-back. A subset of patients reported side effects they consider to be irreversible.