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Cystorelin (Canada)

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


This treatment applies to the following species:
Company: Merial

DIN 02172704

Veterinary use only

Gonadorelin Sterile Solution

50 µg/mL

For the treatment of cystic ovaries in dairy cattle.


CYSTORELIN is a sterile solution of synthetic gonadorelin intended for intramuscular administration.

Each mL of solution contains 50 µg of gonadorelin (GnRH) diacetate tetrahydrate which is equivalent to 43 µg/mL of gonadorelin.

Gonadorelin is a decapeptide composed of the sequence of amino acids-

5-oxo Pro-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2-

It has a molecular weight of 1182.32 and empirical formula C55H75N17O13. The diacetate tetrahydrate ester has a molecular weight of 1374.48 and empirical formula C59H91N17O21.

Gonadorelin is the hypothalamic releasing factor responsible for the release of gonadotropins (e.g., FSH, LH) from the anterior pituitary. Synthetic gonadorelin is physiologically and chemically identical to the endogenous bovine hypothalamic releasing factor.

Active Ingredients

Each mL of solution contains 50 µg of gonadorelin diacetate tetrahydrate.

Cystorelin Indications

CYSTORELIN is a gonadotropin-releasing hormone 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 luteinizing hormone (LH) such as human chorionic gonadotropin. CYSTORELIN initiates release of endogenous LH to cause ovulation and luteinization. The average time to response is 21 days.

Cystorelin Dosage And Administration

Administer a single intramuscular injection at a dose of 100 µg (2 mL) / cow.


Treated animals must not be slaughtered for use as food for at least 7 days after the last treatment with this drug. No milk withholding time is required when used according to the label.

Keep out of reach of children.

Pharmacology And Toxicology

Endogenous gonadorelin is synthesized and/or released from the hypothalamus during various stages of the bovine estrus 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 intramuscularly also causes the release of endogenous LH or FSH from the anterior pituitary.

Gonadorelin diacetate tetrahydrate has been shown to have a low level of toxicity in animals. The LD50 for mouse and rats is greater than 60 µg/kg, and for dogs, greater than 600 µg/kg, respectively. No untoward effects were noted among rats or dogs administered 120 µg/kg/day or 72 µg/kg/day intravenously for 15 days.

It had no adverse effects on heart rate, blood pressure, or ECG 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 of gonadorelin diacetate tetrahydrate to pregnant rats and rabbits during organogenesis did not cause embryotoxic or teratogenic effects.

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

Further, CYSTORELIN does not cause irritation at the site of intramuscular administration in dogs. The dosage administered was a 72 µg/kg/day for seven (7) days.


Store at or below 25°C. Protect from light. DO NOT FREEZE.


CYSTORELIN is available in a concentration of 50 µg/mL pH adjusted with potassium phosphate (monobasic and dibasic).

CYSTORELIN is supplied in multidose vials containing 10 mL and 30 mL of sterile solution.

CYSTORELIN® is a registered trademark of Merial Limited.

Merial Canada Inc., 20000 Clark Graham, Baie d’Urfé, QC, Canada H9X 4B6

CPN: 11820116

Customer Care No.:   1-800-567-1885
Technical Services No.:   1-877-565-5501
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