Effects of an extended-interval dosing regimen of triptorelin depot on the hormonal profile of patients with endometriosis: prospective observational study.

OBJECTIVE: To evaluate the suppression of pituitary gonadotrophins and ovarian steroid hormone with the administration of triptorelin depot at 6-weekly intervals. DESIGN: Prospective observational study. SETTING: Obstetrics and gynaecology department of a public hospital, Hong Kong. PATIENTS: Consecutive patients with endometriosis, as diagnosed by laparoscopy or laparotomy from June 1998 through February 1999. INTERVENTION: Administration of four doses of triptorelin depot 3.75 mg either subcutaneously or intramuscularly every 6 weeks (21 patients), or conventional 4-weekly six-dose regimen (five patients). MAIN OUTCOME MEASURES: Serum levels of 17-beta-oestradiol, luteinizing hormone, and follicle-stimulating hormone; and pelvic pain symptoms. RESULTS: For the patients receiving the extended-interval dosing regimen of triptorelin, the levels of oestradiol and luteinizing hormone, and the pain score were significantly reduced throughout the treatment period and up to 10 weeks after the injection of the last dose. The level of follicle-stimulating hormone increased slowly but was still significantly lower than pretreatment levels. The hormonal profile was similar to that of patients receiving the conventional regimen. CONCLUSION: The use of the extended-interval dosing regimen of triptorelin depot results in a consistent hypo-oestrogenised state, which is similar to that achieved by the conventional regimen and which would be considered satisfactory for the medical treatment of pelvic endometriosis. The new regimen thus reduces the cost of treatment without compromising the effect on hormonal suppression.