Ganirelix
Ganirelix, a peptide. Decapeptide GnRH-R antagonist engineered with D-arginine substitutions at positions 6 and 8 to reduce mast-cell… Subcutaneous half-life 13 h.
Decapeptide GnRH-R antagonist engineered with D-arginine substitutions at positions 6 and 8 to reduce mast-cell histamine release compared with first-generation GnRH antagonists (Antide etc.). Used in IVF / ART controlled ovarian stimulation to block premature LH surge. Reaches suppression rapidly (hours) and effect wanes within 24 h of last dose — smoother endocrine control than agonist protocols.
PK: Oberyé 1999 (PMID:10593371), 15 healthy women evaluated, 0.25 mg SC and IV crossover, verbatim "The mean (+/- SD) half-lives after IV administration and SC administration were highly similar (12.7+/-3.7 hours and 12.8+/-4.3 hours, respectively)" and "resulting in an absolute mean (+/- SD) bioavailability of 91.3%+/-6.7%". Both stored values are supported as stored, and because that study has a real IV arm the bioavailability is genuinely absolute. V 35 L and ka 0.5 /h dropped 2026-09-06: the paper states neither, and a search of the ganirelix literature returns no volume of distribution at all — so pairing an unprovenanced volume with a measured absolute F was the double-count this registry has been removing elsewhere.
Pharmacokinetics
- Subcutaneous — t½ 12.8 h · F 91%
Sources: PMID:1385467