GnRH antagonist
Pronunciation: guh-NAD-oh-trop-in ree-LEE-sing HOR-mohn an-TAG-oh-nist
Also written as: GnRH — gonadotropin-releasing hormone antagonist
A medication that blocks gonadotropin-releasing hormone to prevent premature ovulation. Used in controlled ovarian stimulation protocols.
Full Definition
GnRH antagonists are synthetic compounds that competitively bind to and block gonadotropin-releasing hormone receptors in the pituitary gland. By preventing GnRH action, these medications suppress the release of luteinizing hormone and follicle-stimulating hormone, thereby preventing premature ovulation during controlled ovarian stimulation cycles. Unlike GnRH agonists, antagonists provide immediate suppression without an initial stimulatory phase. Common GnRH antagonists include cetrorelix and ganirelix, which are typically administered as daily subcutaneous injections during the later stages of ovarian stimulation. This approach allows for more flexible cycle management and reduced treatment duration compared to long agonist protocols.
Usage
Usage note: Distinguish clearly from GnRH agonists, which have opposite initial effects; maintain consistency in capitalization of abbreviation.
In Context
- "The antagonist protocol using GnRH antagonist resulted in excellent cycle control with minimal side effects." — Treatment outcome report
- "Daily GnRH antagonist injections were initiated on stimulation day 6 to prevent premature LH surge." — Cycle monitoring notes