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byoo-TORE-fa-nole - Pronunciation guide

Brand Names

  • Butorphic Injection
  • Dolorex
  • Equanol™
  • Torbugesic®
  • TorphaJect™


Rx symbolButorphanol is a synthetic narcotic used for the relief of pain in horses. It may be used alone or in combination with tranquilizers, such as xylazine, detomidine, and other drugs. It is five times more effective in controlling pain than morphine, begins to alleviate pain within 15 minutes of administration, and can be effective for up to four hours.


Butorphanol is used for pain relief, making the horse easier and safer to handle. It provides sufficient sedation and pain control for use in post-partum treatment of mares, surgery, and many other veterinary procedures. It is useful for the relief of pain associated with colic in adult horses and yearlings.

It is also used for sedation, in combination with xylazine, detomidine hydrochloride, and other drugs, and as a cough suppressant.

Dosage and Administration

Prescription medicationButorphanol
Method Dosage
(click row for calculator)
Concentration Period Duration
Intravenous injection 0.1 mg/kg 10 mg/ml Every 3 or 4 hours Not to exceed 48 hours
Intramuscular injection 0.02 mg/kg1 10 mg/ml 2 or 3 times a day NA


  • Federal law restricts this drug to use by or on the order of a licensed veterinarian.
  • Pain relief effects of butorphanol are seen within 15 minutes following injection and persist for about 4 hours.
  • 1For cough.
  • Calculator is for educational purposes only. Follow your veterinarian's instructions regarding use of this, or any medication.

Side Effects

In clinical trials in horses, the most commonly observed side effect was slight ataxia (loss of coordination) which lasted 3 to 10 minutes. Marked ataxia was reported in 1.5% of the 327 horses treated. Mild sedation was reported in 9% of the horses. Transient diarrhea may occur. Central nervous system excitation has been noted with high doses. Salivation, seizures, hyperthermia, and increased GI motility have been noted, but are usually transitory in nature.


There are no well-controlled studies using butorphanol in breeding horses, weanlings, and foals. Therefore, the drug should not be used in these groups.

When sedated, horses can react suddenly and unexpectedly. Extreme caution should be used to prevent mishaps.

Butorphanol is FDA approved for use with horses. It is a prescription drug and a controlled substance. U. S. federal law restricts this drug to use by or on the lawful written or oral order of a licensed veterinarian.

Butorphanol is a prohibited substance and a prohibited class A medication in competitions. It is important to check with the proper individual regulatory group.


Butorphanol should be used with caution with other sedative or analgesic drugs, as these are likely to produce additive effects.


Butorphanol is considered to have a wide margin of safety. In case of overdose, a narcotic antagonist, such as naloxone, may be administered per a veterinarian's recommendation.


Butorphanol Injectable IV or IM 0.1 mg/kg Butorphanol Injectable IV or IM 0.1 mg/kg

Butorphanol Tablet 1, 5 or 10 mg Butorphanol Tablet 1, 5 or 10 mg

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.