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LUT-uh-lyse - Pronunciation guide

Brand Names

  • Lutalyse Injection
  • Lutalyse Sterile Solution


Rx symbolLutalyse Sterile Solution is a natural estrus-synchronization product approved for use in horses. Lutalyse contains a well characterized prostaglandin that occurs naturally in nearly all mammalian tissue.


Lutalyse is used to control estrus time in estrous-cycling mares. Mares treated with Lutalyse during diestrus will return to estrus within 2 to 4 days in most cases. This serves as an aid to scheduling stallions.

In difficult-to-breed mares, treatment with Lutalyse usually results in regression of the corpus lutem followed by estrus and/or ovulation.

Dosage and Administration

Prescription medicationLutalyse
Method Dosage
(click row for calculator)
Concentration Period Duration
Intramuscular injection 1 mg/100lb 5 mg/ml Treatment1 NA


  • Federal law restricts this drug to use by or on the order of a licensed veterinarian.
  • Extra-label use of drugs in treating animals is allowable only by licensed veterinarians within the context of a valid veterinarian-client-patient relationship, and does not include drug use in treating animals by the layman (except under the supervision of a licensed veterinarian).
  • 1Observe for signs of estrus by means of daily teasing with a stallion, and evaluate follicular changes on the ovary by palpation of the ovary per rectum. Some clinically anestrous mares will not express estrus but will develop a follicle which will ovulate. These mares may become pregnant if inseminated at the appropriate time relative to rupture of the follicle.
  • Calculator is for educational purposes only. Follow your veterinarian's instructions regarding use of this, or any medication.

Side Effects

Side effects may include transient decreased body temperature and sweating. Less often increased respiratory and heart rates, ataxia, abdominal pain and lying down may occur. These side effects are generally seen within 15 minutes of administration and resolve within an hour.


Aseptic techniques should be followed in administration to reduce the possibility of post-injection bacterial infections.

Do not administer Lutalyse in pregnant animals unless cessation of pregnancy is desired.

Do not use intravenous administration.

Women of childbearing age and persons with respiratory problems should exercise extreme caution when handling Lutalyse.

Lutalyse is ineffective when administered prior to the fifth day after ovulation.

Despite treatment, mares that terminate pregnancy after 36 days may not return to the presence of functional endometrial cups.

Mares that have either acute or subacute disorders of the vascular system, gastrointestinal tract, respiratory system or reproductive tract should not be treated with Lutalyse.

Not for use in horses intended for human consumption.

Lutalyse is FDA approved for use in horses and federal law restricts this drug to use by or on the order of a licensed veterinarian.

Check with the appropriate individual regulatory board regarding use in competition horses.


None noted.


Lutalyse InjectionLutalyse Injection

Lutalyse Injection Sterile SolutionLutalyse Injection Sterile Solution



About the Author

EquiMed Staff

EquiMed staff writers team up to provide articles that require periodic updates based on evolving methods of equine healthcare. Compendia articles, core healthcare topics and more are written and updated as a group effort. Our review process includes an important veterinarian review, helping to assure the content is consistent with the latest understanding from a medical professional.