A GnRH-antagonist made by Organon. The first to be FDA approved for women undergoing in vitro fertilisation), with good results when started on day 7 of the cycle, after 5 or 6 days FSH in suppressing the LH surge; the dosage, however, appears to be critical, to avoid over-suppressing natural luteinising hormone. Marketed as Antagon in the US and as Orgalutran elsewhere.

The GnRH-antagonist ganirelix made by Organon. Called Orgalutran outside the US.

The GnRH-antagonist ganirelix made by Organon. Called Antagon in the US.