Gnrh
General Drug Information and Indications
Gonadotropin-releasing hormone for induction of ovulation in mares; treatment of cystic ovarian disease; reproductive cycle manipulation.
Gonadotropin-releasing hormone (GnRH) — decapeptide hormone. Mechanism: binds GnRH receptors on pituitary gonadotrophs → G-protein signaling → LH and FSH secretion → gonadal steroidogenesis and follicular development. Pulsatile administration triggers ovulation; used acutely in mares. Available as native GnRH and synthetic analogues (buserelin, deslorelin).
Key information
Gonadorelin — refrigerate. Administer IV or IM. Used in breeding protocols — coordinate with veterinarian for precise timing. Multiple products available (Factrel, Cystorelin, OvaCyst).
How to Give this Medication
IV or IM injection as directed. Mares: administer when follicle ≥35 mm; confirm ovulation 36–48 hrs later by ultrasound. IV route provides faster pituitary stimulation. Store refrigerated (2–8°C); do not freeze. (some formulations); Store at room temperature; protect from light. (others — check label).
If a dose is missed
This medication is administered by a veterinarian or veterinary staff in a clinical setting. Missed doses are managed by your veterinary team — contact your veterinarian to reschedule.
Side Effects
Generally well tolerated. Mares: multiple ovulations → twin pregnancies (monitor by ultrasound). Stallions: antibody formation with repeated use of GnRH analogues. Injection site reactions (mild). Transient increase in LH/FSH (intended).
Precautions
For animals
Monitor by ultrasound for ovulation response. Repeated use of synthetic GnRH analogues: antibody formation → reduced efficacy. Ensure appropriate follicle size before use (typically ≥35 mm in mares).
For people handling this medication
Wear gloves when handling. Wash hands thoroughly with soap and water after handling. Reproductive hormone — Keep out of reach of children. Pregnant women and women of childbearing age should avoid contact. Wear gloves when handling. Avoid skin contact.
Overdose
Contact your veterinarian. GnRH overdose causes initial hormonal stimulation then suppression. Contact vet for guidance.
Gnrh dosage forms
| Product | Strength | Form | Size | Type |
|---|---|---|---|---|
| GNRH 250 MCG/ML INJECTABLE - 2 ML | 250 MCG/ML | Injectable | 2 ML | Compound |
| GNRH 500 MCG/ML INJECTABLE -2 ML | 500 MCG/ML | Injectable | 1 | Compound |
Sources
This information is provided for educational purposes and is not a substitute for advice from your veterinarian. Source: Merck Veterinary Manual – Systemic Pharmacotherapeutics of the Reproductive System (https://www.merckvetmanual.com/pharmacology/systemic-pharmacotherapeutics-of-the-reproductive-system/overview-of-systemic-pharmacotherapeutics-of-the-reproductive-system-in-animals); Plumb's Veterinary Drug Handbook (Plumb, D.C., app.plumbs.com)