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PROE-mah-zeen - Pronunciation guide

Brand Names

  • Promazine Granules
  • Promazine HCL


Rx symbolPromazine is a propylamino phenothiazine derivative that is freely soluble in alcohol and is usually given as an injection or an oral dose of granules.

Promazine is used in horses as a pre-anesthetic agent, often in conjunction with Atropine, and it is generally accepted that the recommended dose will cause moderate sedation in most horses.

Acepromazine has effectively replaced Promazine for use in veterinary medicine, and both Granules and injectible forms may be unavailable.


Promazine is used primarily in horses because of its tranquilizing action. It works as an anti-emetic, anti-spasmodic, and hypothermic agent, and some researchers have reported that it has anti-convulsant properties. Some veterinarians recommend its use in helping control "fractious" animals.

Promazine is also used to lower blood pressure in animals with laminitis and renal failure.

Dosage and Administration

Prescription medication Promazine
Method Dosage
(click row for calculator)
Concentration Period Duration
Intravenous or Intramuscular injection1 0.2-0.5 mg/lb 50 mg/ml Every 4 to 6 hours NA


  • 1For use as a tranquilizer, preanesthetic, or for minor operative procedures in conjunction with local anesthesia; and as adjunctive therapy for tetanus.
  • 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).
  • The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your equine appears to feel better, the entire treatment plan should be completed to prevent relapse.
  • This medication may be available in forms and concentrations not noted in the above table. Always check the label and literature provided with the medication about the form and concentration and DO NOT USE the calculator if the information differs.
  • Calculator is for educational purposes only. Follow your veterinarian's instructions regarding use of this, or any medication.

Side Effects

In large male animals, protrusion of the penis may occur. Excitement, restlessness, sweating, trembling, and, rarely, seizures and recumbency may occur.


Cautious use and smaller doses of promazine should be given to animals with hepatic dysfunction, cardiac disease, or general debilitation.

Intravenous injections should be made slowly.

Promazine is a prescription drug approved for use in horses and U. S. federal law restricts this drug to use by or on the lawful written or oral order of a licensed veterinarian.

Promazine would be banned in any drug-free competition. It is important to check with the individual regulatory group.


Promazine should not be given within one month of worming with an organophosphate agent. Central nervous system depressant agents, barbiturates, narcotics, etc., may cause additive CNS depression if used with promazine. Quididine may cause additive cardiac depression if given with promazine. Antidiarrheal mixtures, such as Kaolin/pectin and antacids, may cause reduced GI absorption of oral phenothiazines.


Massive oral overdoses should be treated by emptying the gut under the direction of a veterinarian, if possible. Doxapram has been suggested as an antagonist to the CNS depressant effects of promazine.




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.