Triptorelin (acetate or pamoate) is a gonadotropin-releasing hormone agonist (GnRH agonist). By causing constant stimulation of the pituitary, it decreases pituitary secretion of gonadotropins luteinizing hormone (LH) and follicle stimulating hormone (FSH). Like other GnRH agonists, triptorelin may be used in the treatment of hormone-responsive cancers such as prostate cancer or breast cancer, precocious puberty, estrogen-dependent conditions (such as endometriosis or uterine fibroids), and in assisted reproduction. Triptorelin is marketed under the brand names Decapeptyl (Ferring Pharmaceuticals) and Diphereline and Gonapeptyl. In the United States, it is sold by Pfizer as Trelstar.

During the treatment of prostate cancer it does cause a surge of testosterone (an initial uplevel of testosterone levels), known as a flare effect. In men a reduction of serum testosterone levels into the range normally seen after surgical castration occurs approximately two to four weeks after initiation of therapy. In contrast, gonadotropin-releasing hormone antagonists do not cause a surge, but a sudden reduction of testosterone levels.
Systematic IUPAC Name: [d-Trp6]GnRH

References

• Lahlou N, Carel JC, Chaussain JL, Roger M (2000). "Pharmacokinetics and pharmacodynamics of GnRH agonists: clinical implications in pediatrics". J Pediatr Endocrinol Metab 13 Suppl 1 723–37.
• Padula AM (2005). "GnRH analogues—agonists and antagonists". Anim Reprod Sci 88 (1-2): 115–26.