Antagon

You should not use this medication if you are allergic to ganirelix or similar medications such as leuprolide (Lupron, Eligard), goserelin (Zoladex), or nafarelin (Synarel).

Before using ganirelix, tell your doctor if you are allergic to latex rubber.

FDA pregnancy category X. This medication can harm an unborn baby or cause birth defects. Do not use ganirelix if you are already pregnant. Your doctor may give you a pregnancy test to make sure you are not pregnant before you receive ganirelix. Tell your doctor right away if you become pregnant during treatment.

It is not known whether ganirelix passes into breast milk or if it could harm a nursing baby. You should not breast-feed while you are being treated with ganirelix.

Ganirelix is injected under the skin. You may be shown how to use injections at home. Do not self-inject this medicine if you do not fully understand how to give the injection and properly dispose of used needles and syringes.

Ganirelix is usually given once daily for several days in a row during certain phases of your fertility treatment cycle. Follow your doctor's instructions and try not to miss any doses.

Each single use vial (bottle) of this medicine is for one use only. Throw away after one use, even if there is still some medicine left in it after injecting your dose.

Use each disposable needle only one time. Throw away used needles in a puncture-proof container (ask your pharmacist where you can get one and how to dispose of it). Keep this container out of the reach of children and pets.

During your treatment with ganirelix, your blood may need to be tested often. Visit your doctor regularly. You must remain under the care of your doctor while using ganirelix.

Store the prefilled syringe at room temperature, away from heat, moisture and light.

Call your doctor for instructions if you miss a dose.

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Applies to ganirelix: subcutaneous solution

Along with its needed effects, ganirelix (the active ingredient contained in Antagon) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking ganirelix:

• Abdominal or stomach pain
• bloating
• diarrhea
• rapid weight gain

• Cough
• difficulty with swallowing
• dizziness
• fast heartbeat
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• shortness of breath
• skin rash, hives, or itching
• tightness in the chest
• unusual tiredness or weakness

Some side effects of ganirelix may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

• Headache
• redness, pain, or swelling at the injection site

Applies to ganirelix: subcutaneous solution

Genitourinary

Genitourinary symptoms of abdominal pain (4.8%), ovarian hyperstimulation (2.4%), and vaginal bleeding (1.8%) have been reported.[Ref]

Nervous system

Nervous systems side effects have been limited to headache in 3% of patients.[Ref]

Local

Local side effects have included non-specific injection site reactions (1.1%).[Ref]

Gastrointestinal

Gastrointestinal side effects of nausea and abdominal pain have occurred in 1.1% and 1% of patients, respectively.[Ref]

Other

Follow-up studies of 282 newborns revealed 3 neonates with major and 18 with minor congenital anomalies. The major anomalies included hydrocephalus/meningocele, omphalocele, and Beckwith-Wiedemann Syndrome. Minor dermal, skeletal, muscular, and organ (angioma, hernia , testes, and renal) anomalies were reported.[Ref]

Neonatal congenital anomalies have been reported. The causal relationship of the anomalies and ganirelix therapy is unknown. Multiple factors may confound assisted reproductive procedures.[Ref]

Hypersensitivity

Hypersensitivity side effects have included postmarketing reports of hypersensitivity reactions, including anaphylactoid reactions with the first dose.

Some side effects of Antagon may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.