Acepromazine, often referred to as Promace, is a tranquilizer that produces sedation in both cats and dogs. It is strictly prescribed under a veterinarian's prescription and has various uses. It is commonly prescribed in particular for car travel in anxious pets, to relieve motion sickness, prior to surgery in conjunction with atropine, to reduce anxiety in fractious animals during grooming sessions and sometimes to relieve itching and scratching.

How Acepromazine Works

The drug works by depressing the central nervous system and by causing a drop in blood pressure. The medication as well has an effect as an anti-emetic, reducing nausea and vomiting episodes in pets that are prone to motion sickness. Acepromazine does not relieve or reduce pain.

Acepromazine Side Effects

Acepromazine may cause side effects in both dogs and cats. As with any medication pets may develop allergies and sensitivities. Common side effects consist of lethargy, unsteadiness (especially in the hind legs), the appearance of the third eyelid in the corner of the eye and droopy eyes. These effects last for several hours.

In more severe cases, Acepromazine may significantly lower blood pressure, body temperature and heart rate. It may also cause seizures in pets prone to them and cause trouble breathing.

In some cases, Acepromazine may cause a totally different effect known as a ''paradoxical reaction''. In this case the pet (it happens most likely in cats) will become hyperactive and sometimes even aggressive instead of becoming calm and sedated.

Brachycephalic Breeds: Words of Caution

Brachycephalic breeds are those with short noses and flat faces. These breeds are more prone to develop complications from the use of Acepromazine. In particular the use of Acepromazine should be avoided all together in Boxer dogs which may develop serious heart problems and very low blood pressure which may result into collapse and respiratory arrest.

Examples of brachycephalic dog breeds are: Boxers, Pugs, Pekignese and Boston Terriers.

Examples of brachycephalic cat breeds are: Persians and Himalayans.

Other Breeds at Risk

Giant dog breeds and Greyhounds are considered as being  particularly sensitive to Acepromazine as well.

Why Acepromazine is Not Recommended for Air Travel

While many vets will prescribe Acepromazine for car travel, many may be reluctant to prescribe it for air travel especially when the pet is planned to travel in the cargo compartment. The reasons behind this are several.

According to Patricia Olson, DVM, director of veterinary affairs and studies for the Englewood, Colo.-based American Humane Association in the article ''Sedating dogs for travel'': Sedation affects a dog's equilibrium. This can impair its ability to steady itself against sudden movements, which can result in injury. High altitudes can create respiratory or cardiovascular problems in sedated dogs.'

Pets That Should Avoid Acepromazine

Owners of pets on other medications shuold consult with their veterinarain about giving Acepromazine as they may develop complications due to interactions. The medication should be avoided (or used with extreme caution according to the veterinarian's advice) in brachycephalic pets as described previously and other breeds at risk, dehydrated debilitated dogs, very young dogs, pregnant or lactating dog, old dogs, dogs with liver or heart disorders and epileptic dogs.

Acepromazine may be a very effective tranquilizer for pets however, there are side effects to be aware of. For this reason, it is often a good idea to reort to lighter sedatives first and work from there. When owners intend to use Acepromazine for a trip they should try it a few days prior to ensure the dog responds to the medication and to determine the correct level of sedation. It is ideal therefore, to start with a low dose and see how the pet responds. Owners should consult with their veterinarian about this protocol and for correct dosing information.