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This page contains information on Fertagyl for veterinary use.
The information provided typically includes the following:
  • Fertagyl Indications
  • Warnings and cautions for Fertagyl
  • Direction and dosage information for Fertagyl


This treatment applies to the following species:
Manufacturer: Intervet/Merck Animal Health



ANADA 200-134, Approved by FDA



Fertagyl is a sterile solution containing 43 µg/mL gonadorelin (GnRH; equivalent to 50 µg/mL gonadorelin diacetate tetrahydrate) suitable for intramuscular or intravenous administration. Gonadorelin is a decapeptide composed of the sequence of amino acids -


with a molecular weight of 1182.32 and empirical formula C55H75N17O13.

Gonadorelin is the hypothalamic releasing factor responsible for the release of gonadotropins (e.g., LH, FSH) from the anterior pituitary.

Synthetic gonadorelin is physiologically and chemically identical to the endogenous bovine hypothalamic releasing factor.


Endogenous gonadorelin is synthesized by and/or released from the hypothalamus during various stages of the bovine estrous cycle following appropriate neurogenic stimuli. It passes via the hypophyseal portal vessels, to the anterior pituitary to effect the release of gonadotropins.

Synthetic gonadorelin administered intramuscularly or intravenously also causes the release of endogenous LH and FSH from the anterior pituitary.

Gonadorelin diacetate tetrahydrate has been shown to be safe. The LD50 for mice and rats is greater than 60 mg/kg, and for dogs, greater than 600 µg/kg, respectively. No untoward effects were noted among rats or dogs administered 120 µg/kg/day intramuscularly or 72 µg/kg/day intravenously for 15 days.

It had no adverse effects on heart rate, blood pressure or EKG, when administered to unanesthetized dogs at 60 µg/kg. In anesthetized dogs it did not produce depression of myocardial or systemic hemodynamics or adversely affect coronary oxygen supply or myocardial oxygen requirements.

The intravenous administration of 60 µg/kg/day gonadorelin diacetate tetrahydrate to pregnant rats and rabbits during organogenesis did not cause embryotoxic or teratogenic effects.

The intramuscular administration of 1000 µg gonadorelin diacetate tetrahydrate to normally cycling dairy cattle had no effect on hematology or blood chemistry.

Further, gonadorelin diacetate tetrahydrate did not cause irritation at the site of intramuscular administration in dogs. The dosage administered was 72 µg/kg/day for 7 days.

Fertagyl Indication And Dosage

Fertagyl (gonadorelin) is indicated for the treatment of ovarian follicular cysts in dairy cattle. Ovarian cysts are non-ovulated follicles with incomplete luteinization which can result in nymphomania or irregular estrus.

Historically, cystic ovaries have responded to an exogenous source of luteinizing hormone (LH) such as human chorionic gonadotropin.

Fertagyl initiates release of endogenous LH to cause ovulation and luteinization.

The recommended intramuscular or intravenous dosage of Fertagyl is 86 µg/cow (2 mL; equivalent to 100 µg gonadorelin diacetate tetrahydrate/cow).

Each mL of Fertagyl contains:


43 µg

Benzyl Alcohol

9 mg

Sodium Chloride

7.47 mg

Water for Injection, PhEur.


pH adjusted with sodium phosphate (monobasic and dibasic).

Keep refrigerated: 2° - 8°C (36° - 46°F).


Federal law restricts this drug to use by or on the order of a licensed veterinarian.

How Supplied

Fertagyl is available in a concentration of 43 µg/mL (equivalent to 50 µg/mL gonadorelin diacetate tetrahydrate) suitable for intramuscular or intravenous administration.

Fertagyl is supplied in multidose vials containing 20 mL of sterile solution (Code No. 021913).

033124 INU240

077922E 8.05

Manufactured for: INTERVET INC., Millsboro, DE 19966

By: INTERVET INTERNATIONAL GmbH, Unterschleissheim - Germany

NAC No.: 10473241

Intervet Inc.

556 MORRIS AVE., SUMMIT, NJ, 07901
Customer Service:   800-521-5767
Order Desk:   800-648-2118
Technical Service (Companion Animal):   800-224-5318
Technical Service (Livestock):   800-211-3573
Fax:   908-473-5560
Every effort has been made to ensure the accuracy of the Fertagyl information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the US product label or package insert.

Copyright © 2015 North American Compendiums. Updated: 2015-04-03