Gonadorelin

Indications

Cystic Ovaries Fertagyl is indicated for the treatment of ovarian follicular cysts in dairy cattle. Ovarian cysts are non-ovulated follicles with incomplete luteinization which result in nymphomania or irregular estrus. Historically, cystic ovaries have responded to an exogenous source of LH such as human chorionic gonadotropin. Fertagyl initiates release of endogenous LH to cause ovulation and luteinization. Reproductive Synchrony Fertagyl is indicated for use with Estrumate (cloprostenol injection) to synchronize estrous cycles to allow for fixed time artificial insemination (FTAI) in lactating dairy cows. Fertagyl is indicated for use with cloprostenol sodium to synchronize estrous cycles to allow for FTAI in beef cows.

Dosage and Administration

Cystic Ovaries The intravenous or intramuscular dosage of Fertagyl is 86 mcg gonadorelin (2 mL) per cow. Reproductive Synchrony For lactating dairy cows, the intramuscular dosage of Fertagyl is 86 mcg gonadorelin (2 mL) per cow, used in reproductive synchrony programs similar to the following: Administer the first Fertagyl injection (2 mL) on Day 0. Administer 2 mL of Estrumate (500 mcg cloprostenol, as cloprostenol sodium) by intramuscular injection 6 to 8 days after the first Fertagyl injection. Administer the second Fertagyl injection (2 mL) 30 to 72 hours after the Estrumate injection. Perform FTAI 8 to 24 hours after the second Fertagyl injection, or inseminate cows on detected estrus using standard herd practices. For beef cows, the intramuscular dosage of Fertagyl is 86 mcg gonadorelin (2 mL) per cow, used in reproductive synchrony programs similar to the following: Administer the first Fertagyl injection (2 mL) on Day 0. Administer 500 mcg cloprostenol (as cloprostenol sodium) by intramuscular injection 6 to 8 days after the first Fertagyl injection. Administer the second Fertagyl injection (2 mL) 30 to 72 hours after the cloprostenol sodium injection. Perform FTAI 0 to 24 hours after the second Fertagyl injection, or inseminate cows on detected estrus using standard herd practices. WARNING AND PRECAUTIONS: Not for use in humans. Keep out of reach of children. WITHDRAWAL PERIODS: No withdrawal period or milk discard time is required when used according to the labeling. To report suspected adverse drug events, for technical assistance or to obtain a copy of the Safety Data Sheet (SDS), contact Intervet at 1-800-211-3573. For additional information about adverse drug experience reporting for animal drugs, contact FDA at 1-888-FDA-VETS, or http://www.fda.gov/reportanimalae PHARMACOLOGY AND TOXICOLOGY: Endogenous gonadorelin is synthesized 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 (e.g., LH, FSH). Synthetic gonadorelin administered intravenously or intramuscularly also causes the release of endogenous LH or FSH from the anterior pituitary. Gonadorelin acetate has been shown to be safe. The LD 50 for mice and rats is greater than 60 mg/kg, and for dogs, greater than 600 mcg/kg, respectively. No adverse effects were noted among rats or dogs administered 120 mcg/kg/day or 72 mcg/kg/day intravenously for 15 days. It had no adverse effects on heart rate, blood pressure, or EKG to unanesthetized dogs at 60 mcg/kg. In anesthetized dogs it did not produce depression of myocardial or system hemodynamics or adversely affect coronary oxygen supply or myocardial oxygen requirements. The intravenous administration of 60 mcg/kg/day of gonadorelin acetate to pregnant rats and rabbits during organogenesis did not cause embryotoxic or teratogenic affects. Further, gonadorelin acetate did not cause irritation at the site of intramuscular administration in dogs with a dose of 72 mcg/kg/day administered for seven (7) days. TARGET ANIMAL SAFETY: In addition to the animal safety information presented in the PHARMACOLOGY AND TOXICOLOGY section, the safety of gonadorelin was established through the review and evaluation of the extensive published literature available for the use of gonadorelin-containing products. The intramuscular administration of 860 mcg gonadorelin (as gonadorelin acetate) on five (5) consecutive days to normally cycling dairy cattle had no effect on hematology or clinical chemistries. In field studies evaluating the effectiveness of gonadorelin for the treatment of ovarian follicular cysts, the incidence of health abnormalities was not significantly greater in cows administered gonadorelin than cows administered a placebo injection. The target animal safety of, and injection site reactions to, Fertagyl when used with Estrumate (cloprostenol injection) were evaluated during the conduct of effectiveness field studies in lactating dairy cows. The incidence of health abnormalities was not significantly greater in cows administered Fertagyl than cows administered a placebo injection. The target animal safety of, and injection site reactions to, gonadorelin when used with cloprostenol sodium were evaluated during the conduct of effectiveness field studies in beef cows. The incidence of health abnormalities was not significantly greater in cows administered gonadorelin than cows administered a placebo injection.

Description

Fertagyl is a sterile solution containing 43 mcg/mL of gonadorelin (GnRH: as gonadorelin acetate) suitable for intramuscular or intravenous administration according to the indication. Gonadorelin is a decapeptide composed of the sequence of amino acids - 5-oxoPro-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH 2 a molecular weight of 1182.32 and empirical formula C 55 H 75 N 17 O 13 . Each mL of Fertagyl contains: Gonadorelin (as gonadorelin acetate) 43 mcg Benzyl Alcohol 9 mg Sodium Chloride 7.47 mg Water for Injection, USP q.s. pH adjusted with sodium phosphate (monobasic and dibasic). Gonadorelin is the hypothalamic releasing factor responsible for the release of gonadotropins (e.g., luteinizing hormone [LH], follicle stimulating hormone [FSH]) from the anterior pituitary. Synthetic gonadorelin is physiologically and chemically identical to the endogenous bovine hypothalamic releasing factor.

Other labels for this ingredient

These labels are also stored for the same active ingredient. They are not identical to the one reprinted above, and each is listed by product and set id rather than merged with it.

• , Bimeda, Inc.. Set id e8b1e43c-5227-4a20-a052-c68418b42261.
• GONABREED, Parnell Technologies Pty Ltd. Set id 9bc44a48-ff45-468a-a60d-c490a667d91d.
• CYSTORELIN ® (gonadorelin) 50 mcg/mL gonadorelin diacetate tetrahydrate Injectable Solution, Boehringer Ingelheim Animal Health USA Inc.. Set id 50cf9edb-f318-41d2-9b98-6ea3410e8128.

FDA adverse event reports

The FDA Center for Veterinary Medicine publishes the adverse event reports it receives through openFDA. The counts below are the reports naming gonadorelin as an active ingredient for each species this label names, as returned on 2026-09-16, coded by the VeDDRA reaction term the reporter chose. Reactions are counted per report, so one report can appear under several terms.

These are counts, not rates. Reporting is voluntary, the number of animals treated is not known, and a widely used product accumulates reports for that reason alone. A report records that an event followed a dose; it does not establish that the product caused it. The counts say nothing about how one product compares with another.