Gallagher JS, et al. - The authors here investigated 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. Despite significant side effects, GnRHa plus add-back was observed by subjects as effective. Even they would recommend it to others. Compared to those who received standard add-back, those who received two drug add-back reported more success. Irreversible side effects were reported by a subset of patients.