Overview
Triptorelin is absorbed rapidly after subcutaneous or intramuscular injection with a Tmax of approximately 1–3 hours (aqueous formulation). It binds extensively to pituitary GnRHRs with a Kd in the low nanomolar range. The LH surge peaks at 4–8 hours post-injection; FSH peaks slightly later (~6–10 hours). Downstream testosterone surge in males peaks at 24–72 hours. The aqueous half-life is ~7–8 hours; depot (microsphere) formulations achieve sustained plasma levels over 1 or 3 months. Metabolism occurs via peptidase cleavage; renal elimination of metabolites. Bioavailability via SC/IM routes is ~97%.
Proposed mechanism
Triptorelin binds with high affinity to GnRH receptors on anterior pituitary gonadotrophs; a single low dose produces a brief 'flare' effect—stimulating LH and FSH release—which can serve as a diagnostic or restorative signal to the HPG axis. With repeated or continuous dosing, receptor downregulation and pituitary desensitization lead to profound suppression of LH, FSH, and consequently gonadal testosterone and estrogen synthesis. The paradox of agonist-induced suppression makes dosing strategy critical: a single very low dose (100–500 mcg) is hypothesized to 'reset' a suppressed axis, whereas chronic high-dose use results in medical castration.
What the evidence supports
Randomised controlled trial data in humans exists and supports use in specific contexts.
Graded Clinical
Findings supported by randomised, controlled trials in humans, with pre-registered endpoints and published results.
Key citations
Representative primary sources, including results that did not favour the compound.
- [1]
Moore HC et al. Goserelin for ovarian protection during breast-cancer adjuvant chemotherapy (POEMS/S0230)
· New England Journal of Medicine 2015;372:923–932 · 2015
- [2]
Triptorelin in the management of prostate cancer: pharmacology, clinical efficacy, and tolerability
· Therapeutics and Clinical Risk Management 2007;3(3):433–448 · 2007
- [3]
Crawford ED et al. Leuprolide with and without flutamide in prostate cancer — implications for GnRH analogue flare management
· New England Journal of Medicine 1989;321:419–424 · 1989
- [4]
Scally MC, Kazmer JJ. A novel strategy for the use of gonadotropin-releasing hormone (GnRH) agonists in the treatment of steroid-induced hypogonadotrophic hypogonadism
· European Journal of Clinical Pharmacology 2003;59:21–26 · 2003
Citation records in this build are illustrative placeholders for the design.
Reference information for research purposes. Not medical advice, and not a recommendation to use any compound. Many entries describe substances that are not approved for human use.