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


This treatment applies to the following species:
Manufacturer: Zoetis


For Injection

NADA 139-237, Approved by FDA

For the treatment of cystic ovaries in cattle.

Factrel Caution

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


FACTREL (gonadorelin hydrochloride) is a sterile solution containing 50 micrograms of synthetic gonadorelin (as hydrochloride) per mL in aqueous formulation containing 0.6% sodium chloride and 2% benzyl alcohol (as a preservative).

Gonadorelin is the gonadotropin releasing hormone (GnRH) which is produced by the hypothalamus and causes the release of the gonadotropin luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary.

FACTREL (gonadorelin hydrochloride) has the identical amino acid sequence as endogenous gonadorelin; 5-oxo Pro-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2 with identical physiological activities. The molecular weight of gonadorelin is 1182 with a molecular formula of C55H75N17O13. The corresponding values for gonadorelin hydrochloride are 1219 (1 HCl) expressed as C55H75N17O13HCl, or 1255 (2 HCl) expressed as C55H75N17O13 2HCl.

Mechanism Of Action

Follicular cysts are enlarged non-ovulatory follicles resulting from a malfunction of the neuroendocrine mechanism controlling follicular maturation and ovulation. Exogenous administration of agents possessing luteinizing hormone (LH) activity, such as pituitary extracts or human chorionic gonadotropin, often causes ovulation or regression of follicular cysts. FACTREL induces release of endogenous luteinizing hormone (LH) to produce this same effect.

No significant differences have been demonstrated in days from treatment to conception, frequency of cows conceiving at first or subsequent heats, or conception rates among treated or non-treated control animals.

Factrel Indications

FACTREL (gonadorelin hydrochloride) is indicated for the treatment of ovarian follicular cysts in cattle. The treatment effect of FACTREL when used in cattle with ovarian follicular cysts is a reduction in the number of days to first estrus.


The recommended dosage of FACTREL is 100 mcg/cow intramuscularly.

Residue Warning

Because FACTREL is identical to endogenous GnRH such that both are rapidly metabolized without detectable levels in milk or tissue, no withdrawal period is required.

Storage Conditions

Store at refrigerator temperature 2° to 8°C (36° to 46°F).

Safety And Toxicity

In cows the intramuscular administration of up to 25 times recommended dosage (2,500 mcg/day) of FACTREL for 3 days did not affect any physiological or clinical parameter. Likewise, single intramuscular doses of 5 times recommended dosage (500 mcg) did not interfere with pregnancy. No evidence of irritation at injection site was found in any animal.

How Supplied

FACTREL (gonadorelin hydrochloride) solution 50 mcg/mL is available in 20 mL multidose vials (box of one).

NDC 0856-4311-02 - 20 mL - box of 1

Fort Dodge Animal Health, Fort Dodge, Iowa 50501 USA


Rev. Apr. 2003


NAC No.: 10030712

Telephone:   269-833-4000
Customer Service:   800-733-5500 and 800-793-0596
Veterinary Medical Investigations & Product Support:   800-366-5288
Technical Services (USA):   800-366-5288
Every effort has been made to ensure the accuracy of the Factrel 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 © 2018 North American Compendiums. Updated: 2018-04-26