Brand Name: Antagon Injection®
Active Ingredient: ganirelix acetate
Strength(s): 250 mcg/0.5 ml
Dosage Form(s): Injection
Company Name: Organon, Inc.
Availability: Prescription only
Date Approved by FDA: July 29, 1999

What is Antagon?

Antagon is used to inhibit premature ovulation in women undergoing fertility procedures.

Who should not use Antagon?

• Women who have experienced a hypersensitivity reaction to gonadotropin-releasing hormone (GnRH) or any other GnRH-type drug.
• Women who suspect or know they are pregnant.

Special Warnings with Antagon:

• A physician specializing in fertility treatment should prescribe Antagon.
• Before starting treatment with Antagon, pregnancy must be ruled out.

General Precautions with Antagon:

• Patients with hypersensitivity to GnRH should be closely monitored after the first injection.
• The packaging of Antagon contains natural rubber latex that may cause allergic reactions.
• You will need to be examined on a regular basis when using Antagon.

What should I tell my doctor or health care provider?

Tell your doctor if you are pregnant or breast-feeding. Women who are pregnant or breast-feeding should not use Antagon.

What are some possible side effects of Antagon? (This is NOT a complete list of side effects reported with Antagon. Your health care provider can discuss with you a more complete list of side effects.)  

The most frequent side effects of Antagon are:

• Abdominal pain
• Fetal death
• Headache

Posted: 5/2/00
Updated: 10/31/00, 12/29/04