Cystorelin (GnRH) Sterile Solution Injection
Cystorelin® is an FDA-approved injectable containing gonadorelin, a synthetic gonadotropin-releasing hormone (GnRH), for veterinary use. Available by prescription.
Cystorelin is FDA-approved for the treatment of ovarian follicular cysts in dairy cattle, and — in combination with cloprostenol — to synchronize estrous cycles for fixed-time artificial insemination in dairy and beef cows. Beyond this approved cattle indication, veterinarians may also consider gonadorelin and other GnRH-class hormones off-label in other species — for example, to help time ovulation in mares as part of a breeding program, or as part of a diagnostic workup for suspected cryptorchidism in dogs and cats. Any use outside the approved cattle indication is extra-label and rests on your veterinarian's professional judgment.
At a pharmacological level, gonadorelin is a synthetic analog of endogenous gonadotropin-releasing hormone. It acts on the anterior pituitary gland to stimulate release of luteinizing hormone (LH) and, to a lesser extent, follicle-stimulating hormone (FSH). In cattle with ovarian follicular cysts, this LH surge is understood to promote ovulation or luteinization of the cystic structure. Because the same hypothalamic-pituitary-gonadal pathway is present across mammalian species, the same basic mechanism underlies its use in other reproductive contexts, though dosing and response vary by species.
The actions described here reflect the product's FDA-approved labeling in cattle; your veterinarian determines the appropriate use for your animal, including any extra-label application in other species.
Prescription only. Use only under the direction of a licensed veterinarian. This information is not a substitute for veterinary diagnosis, prescribing, or monitoring.
In cattle field studies, the incidence of health abnormalities was not significantly greater with Cystorelin than with a placebo injection; commonly observed effects with any injectable hormone can include mild, transient discomfort or swelling at the injection site. Because gonadorelin acts on the reproductive hormone axis, your veterinarian will time administration carefully relative to your animal's reproductive cycle or breeding program. Repeated or high-dose use of GnRH-class hormones over extended periods is associated with downregulation of GnRH receptors, which is why dosing protocols are managed closely by your veterinarian.
This medication is typically used with caution or avoided in animals with a known hypersensitivity to gonadorelin. Provide your veterinarian with a complete history of all other hormonal therapies (such as prostaglandins like cloprostenol) your animal is receiving, since these are often used together as part of a synchronized protocol and timing matters. Store the product as directed on the label and follow standard precautions when handling and disposing of needles and syringes. Contact your veterinarian if you observe signs of a local injection-site reaction or any unexpected behavioral changes following administration.
Yes. Cystorelin is a prescription medication and can only be dispensed by a licensed pharmacy upon receipt of a valid authorization from a licensed veterinarian. Mixlab verifies all authorizations before any medication is prepared or shipped.
In limited circumstances. Cystorelin is available as a commercial, FDA-approved injectable, and federal law places restrictions on compounding a copy of a commercially available product. If your veterinarian determines that a different strength or volume is medically necessary and not commercially available, Mixlab can evaluate a compounded option on a case-by-case basis.
Veterinarians are legally permitted to prescribe FDA-approved animal drugs for extra-label use in other species when they determine it's appropriate for a specific patient. For gonadorelin specifically, this most commonly comes up in equine breeding programs to help time ovulation, or as part of a cryptorchidism diagnostic workup in dogs and cats. This decision, and any related monitoring, is made by the prescribing veterinarian.
According to the manufacturer's labeling, no withdrawal period or milk discard time is required for cattle when Cystorelin is used according to the label. Your veterinarian can advise on any considerations specific to your animal's use case.
