FACTREL - Veterinarians
July 2, 2013
Revised April 24, 2015
Dear Bovine Veterinarian:
In June 2013, FDA approved the second gonadotropin releasing hormone (GnRH) product, FACTREL, for estrous synchrony in lactating dairy cows. FACTREL is a sterile injectable solution of gonadorelin hydrochloride, and when used with LUTALYSE (dinoprost tromethamine) as part of a synchronization regimen, the drug can be used to synchronize estrous cycles to allow fixed time artificial insemination in lactating dairy cows. FDA also wants to remind you of the benefits of using FDA- approved drugs.
|Application Type||New Animal Drug Application (NADA)|
For use with LUTALYSE (dinoprost tromethamine) Sterile Solution to synchronize estrous cycles to allow fixed-time artificial insemination (FTAI) in lactating dairy cows.
(FACTREL is already approved for the treatment of cystic ovaries in cattle.)
|Active Ingredient||Gonadorelin hydrochloride|
|Concentration||50 mcg gonadorelin (as gonadorelin hydrochloride)/mL|
|How Supplied||20 mL multi-dose vials|
|Route of Administration||Intramuscular injection|
The recommended intramuscular dosage is 100 to 200 mcg of gonadorelin (2 to 4 mL) per cow, used in estrous synchrony programs similar to the following:
Endogenous gonadorelin is the gonadotropin releasing hormone (GnRH) that causes the anterior pituitary gland to release gonadotropins, such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Endogenous gonadorelin is synthesized and/or released from the hypothalamus during various stages of the bovine estrous cycle following appropriate neurogenic stimuli.
FACTREL is a sterile solution of synthetic gonadorelin and has the identical amino acid sequence as endogenous gonadorelin.
Endogenous gonadorelin, through release of LH, induces ovulation of dominant ovarian follicles present on the bovine ovary during the estrous cycle. FACTREL has the same effect as endogenous gonadorelin to induce ovulation.
Please refer to the Freedom of Information Summary and package insert for FACTREL before using the drug.
Benefits of FDA Approval
FDA rigorously evaluates an animal drug before approving it. As part of the approval process, the drug company must prove to FDA that:
- The drug is safe and effective for a specific use in a specific animal species;
- The manufacturing process is adequate to preserve the drug’s identity, strength, quality, and purity; and
- The drug’s labeling is truthful and non-misleading.
For a drug intended to be used in food-producing animals, FDA’s approval process also ensures that food products, such as milk and meat, from treated animals are safe for people to eat.
FDA’s role does not stop after the agency approves an animal drug. As long as the drug company markets the animal drug, the agency continues to monitor:
- The drug’s safety and effectiveness. Sometimes, the agency’s post-approval monitoring uncovers safety and effectiveness issues that were unknown at the time of approval;
- The manufacturing process to ensure quality and consistency are maintained; and
- The drug’s labeling to make sure the information remains truthful and non-misleading.
Other Gonadorelin Products
Five gonadorelin (GnRH) products are FDA-approved to treat cystic ovaries in dairy cows, but only three are also FDA-approved for use with another drug for synchronizing estrous cycles in lactating dairy cows: GONABREED, FACTREL, and FERTAGYL.
FDA-approved GnRH Products for Use with Another Drug for Estrous Synchrony
|FACTREL Injection||GONABREED Injectable Solution||FERTAGYL |
|Manufacturer||Zoetis Inc.||Parnell Technologies Pty Ltd||Intervet Inc.|
|Active Ingredient||Gonadorelin hydrochloride||Gonadorelin acetate||Gonadorelin acetate|
|For Estrous Synchrony, Use With:||LUTALYSE (dinoprost tromethamine)||Cloprostenol sodium||ESTRUMATE (cloprostenol injection)|
|Species/Class||Lactating dairy cows||Lactating dairy cows and beef cows||Lactating dairy cows|
Other than the three uses listed in the table above, it is illegal to use GnRH products with another drug for estrous synchrony.
By prescribing FDA-approved FACTREL, you’re choosing one of the three marketed GnRH products shown to be safe and effective for use with another drug for synchronizing estrous cycles in lactating dairy cows. Used together in a breeding program, FACTREL and LUTALYSE synchronize estrous cycles to allow fixed-time artificial insemination in lactating dairy cows.
FDA’s Center for Veterinary Medicine (CVM) is committed to promoting and protecting animal health by ensuring safe and effective drugs are available for animals. For more information, please contact CVM's Education & Outreach Staff at 240-402-7002 or AskCVM@fda.hhs.gov.
Daniel G. McChesney, Ph.D.
Director, Office of Surveillance and Compliance
FDA Center for Veterinary Medicine