Acepromazine maleate is a phenothiazine derivative that is used as a neuroleptic agent in veterinary medicine. It is a commonly used tranquilizer for dogs, cats, and horses. Phenothiazines decrease dopamine levels and depress some portions of the reticular activating system. Acepromazine is metabolized by the liver and excreted in the urine.

In addition to tranquilization, acepromazine has multiple other important systemic effects including anti-cholinergic, anti-emetic, antispasmodic, antihistaminic, and alpha-adrenergic blocking properties. Acepromazine causes hypotension due to decreased vasomotor tone. It may change heart and respiratory rate and thermoregulatory ability allowing for either hypo- or hyper-thermia.


Acepromazine may be given intramuscularly, intravenously, or orally. It provides no analgesia and the tranquilizing effect of the drug can be overcome unexpectedly, particularly by sensory stimulation. Acepromazine usually is less effective if given after the animal is excited. There is a great deal of individual variability in the response to acepromazine and despite being a very commonly used medication there are important species and even breed differences in response to acepromazine that need to be taken into consideration (see precautions).

Features of Acepromazine For Dogs

Acepromazine maleate (brand names and alternative names: acetylpromazine, ACE, ACP, PromAce®) is a sedative/tranquilizer used as a pre-anesthetic and for chemical restraint in dogs and cats. Its use in small exotics as a pre-anesthetic or tranquilizer is ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

Dosage and Administration

Dogs: 0.25-1.0 mg/lb of body weight. Dosage may be repeated as required. Animal safety: Acute and chronic toxicity studies have shown a very low order of toxicity for acepromazine maleate. A safety study using elevated dosages of acepromazine maleate demonstrated no adverse reactions even when administered at three times the upper limit of the recommended daily dosage (3.0 mg/lb body weight). The clinical observation for this high dosage was mild depression which disappeared in most dogs 24 hours after termination of dosing. The only occurrence of adverse reaction during numerous clinical trials was a very mild respiratory distress (reverse sneeze) which was transient in nature and had no effect on the desired action of the drug.

Side Effects of Acepromazine For Dogs

  • Common: Acepromazine will cause hypotension, decreased respiratory rate, and bradycardia. Dogs are particularly sensitive to cardiovascular side-effects but cardiovascular collapse also has occurred in cats. Sudden collapse, decreased or absent pulse and breathing, pale gums, and unconsciousness may occur in some animals.
  • Rare: fatal interactions with anesthetics have been reported.
  • Acepromazine will cause a dose-dependent decrease in hematocrit in both dogs and horses. This effect occurs within 30 minutes of administration and may last for 12 hours or more. The hematocrit in horses may decrease by as much as 50%.
  • Penile paralysis is a rare but recognized adverse side-effect of acepromazine use in the horse. This drug should be avoided in breeding stallions.


  • Acepromazine lowers blood pressure. It should not be used in animals that are dehydrated, anemic, or in shock.
  • Acepromazine should be avoided or used with extreme caution in older animals or those with liver disease, heart disease, injury, or debilitation. If it is used in these animals, it should be given in very small doses. In some older animals, a very small dose can have a marked and very prolonged effect.
  • Acepromazine should not be used in animals with a history of epilepsy, those prone to seizures, or those receiving a myelogram because it may lower the seizure threshold.
  • Acepromazine should not be used in animals with tetanus or strychnine poisoning.
  • Acepromazine should be avoided in pregnancy or lactation. It should be avoided or used with extreme caution in young animals due to its effects on an animal’s ability to thermo regulate.
  • Dogs: Giant breeds and greyhounds may be extremely sensitive to acepromazine, while terriers may require higher doses. Brachycephalic breeds, especially Boxers, are particularly prone to cardiovascular side-effects (drop in blood pressure and slow heart-rate). Acepromazine should be avoided or used with great caution in these breeds.
  • Horses: Draft-horse breeds are especially sensitive to most sedatives including acepromazine. Pony breeds do not appear to differ from horses in their responses to acepromazine.

Prices of Acepromazine For Dogs

$20.43 – $34.39

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