Antagon (Ganirelix)

Description

Antagon (Ganirelix) is a medication classified as a gonadotropin-releasing hormone (GnRH) antagonist. It works by blocking the effects of GnRH, a hormone that signals the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland. By blocking the release of LH and FSH, Ganirelix prevents premature ovulation in women undergoing fertility treatment of controlled ovarian hyperstimulation.

Directions

Ganirelix is administered as a subcutaneous injection. The usual dose is 250 mcg daily during the middle to latter part of the follicular stage, after starting FSH therapy on the cycle’s second or third day. The Ganirelix injection should only be administered under the supervision of a healthcare provider experienced in infertility treatment.

Ingredients

The active ingredient in Antagon is ganirelix acetate.

Contraindications

Avoid taking or using this medication if any of the following apply:

• Known or suspected pregnancy
• Hypersensitivity to Ganirelix, LHRH or LHRH analogs
• History of severe allergic reactions to gonadotropin-releasing hormone (GnRH) or GnRH analogs

Cautions

• Before taking Ganirelix, tell your doctor about any of the following:
• If you have an allergy to Ganirelix or similar medications
• About all medications you take, especially if you are taking hormonal treatments or other medications that may interfere with hormone regulation.
• About any medical conditions you have, including liver and kidney problems.
• If you are pregnant or plan to become pregnant, Ganirelix may cause harm to an unborn baby.
• If you are breastfeeding or plan to breastfeed. Ganirelix can pass into your breastmilk and can cause harm to your baby.
• Ganirelix is given via injection and can lead to itching, swelling, or redness at the site of injection. If these symptoms persist or get worse, reach out to your healthcare provider.
• Be vigilant for signs of Ovarian Hyperstimulation Syndrome (OHSS), a condition that could be severe. These signs may include feelings of bloating or pain in the abdomen, nausea, vomiting, or sudden weight gain.
• Immediate medical assistance may be necessary if you experience difficulties with breathing, develop a rash or hives, or notice swelling in your face, eyes, lips, tongue, or throat after using Ganirelix, as these could indicate serious allergic reactions.
• Certain drugs may interact with Ganirelix, influencing its efficacy or leading to unwanted side effects. Make sure to tell your healthcare provider about any other medications you’re currently taking.
• Supervision by a healthcare professional is necessary to monitor hormonal levels and ovarian response during Ganirelix treatment.

Side Effects

As with any medication, there are potential side effects to consider before starting treatment. The most common side effects of Ganirelix include stomach pain, headache, and vaginal bleeding. These side effects are usually mild and go away on their own. However, if they persist or become severe, it is important to contact a healthcare provider.

In rare cases, Ganirelix may cause more serious side effects. These may include symptoms or signs of an allergic reaction, such as skin rash, swelling of the face, lips, tongue, or throat, and difficulty breathing. If any of these symptoms occur, it is important to seek medical attention immediately.

References:

1. Antagon (Ganirelix) Prescribing Information. Merck & Co., Inc. Accessed August 9, 2023.
2. Antagon (Ganirelix) Drug Label. West Orange, NJ: Organon, Inc.; 2023.

About Dr. Gerardo Sison (Page Author)

An honors graduate of the University of Florida, Dr. Sison started his pharmacy career in a community setting, extending his services to hospitals and clinics over time. He has also worked in medication therapy management, advising patients on proper medication use for their chronic health conditions. Read More....