ganirelix (Rx)

Brand and Other Names:Antagon, Orgalutran

Dosing & Uses


Dosage Forms & Strengths

prefilled syringe

  • 250mcg/0.5mL

Female Infertility

250 mcg SC qDay during mid-to-late phase after initiating follicle-stimulating hormone (FSH) on day 2 or 3 of cycle

Continue treatment until day of chorionic gonadotropin administration

Safety and efficacy not established


Adverse Effects


Abdominal pain (1%)

Headache (3%)

Injection site recation (1%)

Nausea (1%)

Ovarian hyperstimulation syndrome (2%)

Vaginal bleeding (2%)

Pelvic pain (5%)


Anaphylactoid reactions

Postmarketing Reports






Known or suspected pregnancy

Hypersensitivity to ganirelix, LHRH or LHRH analogs


Exclude pregnancy before initiating therapy

Packaging may contain latex products, which may cause allergic reaction in susceptible patients

Use caution in women with sign and symptoms of active allergic conditions


Pregnancy & Lactation


Contraindicated in pregnant women

Animal data

  • When administered from Day 7 to near term to pregnant rats and rabbits at doses up to 10 and 30 mcg/day (~0.4 to 3.2 times the human dose based on body surface area), ganirelix acetate increased the incidence of litter resorption
  • There was no increase in fetal abnormalities
  • No treatment-related changes in fertility, physical, or behavioral characteristics were observed in the offspring of female rats treated with ganirelix acetate during pregnancy and lactation


Should not be used by lactating women

Unknown whether drug is excreted in human milk

Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for the drug, and any potential adverse effects on the breastfed infant from the drug or from the underlying maternal condition

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.



Mechanism of Action

Gonadotropin releasing-hormone antagonist; blocks endogenous LHRH in pituitary with high antagonistic activity & inhibits premature LH surges in patients undergoing controlled ovarian hyperstimulation; prevents ovulation until follicles are of adequate size


Peak plasma concentration 14.8 ng/mL (single-dose); 11.2 ng/mL (multiple-doses)

Peak plasma time: 1.1 hr

AUC: 96 ng·hr/mL (single-dose); 77.1 ng·hr/mL (multiple doses)

Bioavailability: 91.1%


Vd: 43.7 L (IV)

Protein bound: 91.1%


Half-life: 12.8 hr (single-dose); 16.2 hr (multiple doses)

Excretion: Feces (75.1%); urine (22.1%)



SC Administration

SC use only

Recommended SC injection sites are in the abdomen around the navel or upper thigh

Clean about 2 inches around where the needle will be inserted

Pinch up a large area of skin between the finger and thumb; insert at the base of the pinched-up skin at an angle of 45-90° to the skin surface

When the needle is correctly positioned, it will be difficult to draw back on the plunger

Once needle is correctly placed, depress plunger

Discard syringe after use


Store at 20-25°C (68-77°F); excursions permitted between 15-30°C (59-86°F)

Protect from light



ganirelix subcutaneous
250 mcg/0.5 mL solution

Copyright © 2010 First DataBank, Inc.


Patient Handout

Patient Education
ganirelix subcutaneous


(GAN-i-REL-ix AS-e-tate)


USES: This medication is used by women having certain fertility treatments (controlled ovarian stimulation). Ganirelix is usually used in combination with other hormones (FSH and hCG). It works by blocking the release of a certain hormone (luteinizing hormone). Ganirelix stops eggs from being released too early and gives the eggs time to grow properly.

HOW TO USE: Read the Patient Information Leaflet if available from your pharmacist before you start using ganirelix and each time you get a refill. If you have any questions, ask your doctor or pharmacist.Learn all preparation and usage instructions from your health care professional and the product package.Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid.Inject this medication under the skin as directed by your doctor, usually once a day for several days. Carefully follow your doctor's instructions on when to start and stop this medication.Before injecting each dose, clean the injection site with rubbing alcohol. Change the injection site each time to lessen injury under the skin.Use this medication exactly as directed by your doctor to get the most benefit from it. Do not increase your dose or use this drug more often or for longer than prescribed.Learn how to store and discard medical supplies safely.

SIDE EFFECTS: Redness or pain at the injection site, headache, mild nausea/stomach pain, or tiredness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, such as: unusual vaginal bleeding.This medication may cause a condition known as ovarian hyperstimulation syndrome (OHSS). This condition may occur during or after treatment. Rarely, serious OHSS causes fluid to suddenly build up in the stomach, chest, and heart area. Get medical help right away if you develop the following side effects: severe pain or swelling in the lower abdominal (pelvic) area, severe nausea/vomiting, sudden/rapid weight gain, or decreased urination.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, such as: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before using ganirelix, tell your doctor or pharmacist if you are allergic to it; or to other products containing gonadotropin releasing hormone (GnRH); or if you have any other allergies. This product may contain inactive ingredients (such as latex), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history.Before having surgery, tell your doctor or dentist about all the products you use (such as prescription drugs, nonprescription drugs, and herbal products).Multiple births may occur as a result of this treatment. Consult your doctor for more details.Stop using this medication when you become pregnant. This medication must not be used during pregnancy. If you think you may be pregnant, tell your doctor right away.It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this drug. Consult your doctor before breastfeeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (such as prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

NOTES: Do not share this medication with others.Lab and/or medical tests (such as vaginal ultrasound, hormone levels, liver tests) may be done while you are using this medication. Keep all medical and lab appointments. Consult your doctor for more details.

MISSED DOSE: If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule. Do not double the dose to catch up.

STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Information last revised October 2023. Copyright(c) 2023 First Databank, Inc.

IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.



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Tier Description
1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
NC NOT COVERED – Drugs that are not covered by the plan.
Code Definition
PA Prior Authorization
Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
QL Quantity Limits
Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
ST Step Therapy
Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
OR Other Restrictions
Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.