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The use of Acepromazine in Dogs and Cats

Adrienne is a certified dog trainer, former veterinary assistant, and author of the online dog training course "Brain Training for Dogs."


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. Also, it's been found that certain breeds with the MDR1 gene mutation may need lower dosages. Here's a list of dogs with the MDR1 gene mutation: Dogs Sensitive to Acepromazine.

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 report 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.

Disclaimer: this article is not to be used as substitute for professional veterinary advice. If your dog is sick or requires medication please see your veterinarian.

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Dawn Marie on October 09, 2020:

Benadryl works exactly the same peeps with a lot less dangerous side effects. Such as it’s for allergies, which in turn should be tons less risky for pets with any respiratory issues? I don’t suggest Benadryl decongestunless your dog had sinus allergies and it’s needed as most decongestant are more sedative? But check with your vet it is far more safe, my pharmacist gave me instructions for my pup who was on chemo and it was a god send and cheap as I’m disabled with no back up for survival so vets can be tricky unless of course it’s a must do I’ll go without? You can google Benadryl and pup or cats weight? I think this OTC Med covers most of the issues I read in the comment so my best wishes to all you peeps and your beloved fur babies. From one huge animal lover to all you animal lovers!

Adrienne Farricelli (author) on February 04, 2012:

It seems like this medication is difficult to dose correctly. I had the same problem with my cat, the dose the vet prescribed did not seem to work, so I called him and he told me to increase it. Afterward my cat started acting quite oddly; staggering, looking into space, I was really worried! Luckily, the effect wore off after a few hours.

Bill on February 04, 2012:

Our Westie (Callie) was prescribed ACP to calm her down during thunderstorms. At first, one half (1/2) dose of ACP seemed to work well, but this morning was a total disaster. Callie was unable to steady herself after several hours. This was not an issue during first use of ACP. The remainder of this prescription has been flushed down the toilet. Even at half dose, ACP is way too strong for Callie.

Paulart from 2510 Warren Avenue Cheyenne,Wyoming 82001 on January 30, 2012:

Very useful information is given on this hub.

Charlotte on January 06, 2012:

I'm not a vet however I work weekends with my vet and he has occasionally used ACP as a sedative in aggressive or difficult dogs. It is usually effective in 30 minutes and should have worn off in 10 hours - usually a lot less. Dry nose, unsteadiness, etc are usual signs but breathing is not something I have noticed before. I'm not an expert and don't claim to be - your best course of action would be to see your vet and take your dog ASAP however I just thought my experience with the drug might help someone. My own dog is currently sleeping it off after vommiting quite a lot today and me being unable to get my usual drug (cerenia) which I prefer. I know the effects of ACP are alarming at first especially with dogs that it hits hard - my dog will spend a whole day asleep but it's required sometimes. I wouldn't recommend it though if you had an alternative.

Adrienne Farricelli (author) on January 04, 2012:

Millie, not sure what you mean by ''phenomena'', do you mean your dog is still suffering from the side effects? what did your vet say? The symptoms should have improved by now. I really can't tell you if this is something ''survivable'' I guess it really depends on an individual basis, just as some people have allergic reactions to medications. This medication really should not be used in senior dogs. Let your vet know, about these continuing problems,hoping the best.

Millie on January 03, 2012:

She went to the vet yesterday. She might have phenomena now. Can dogs survive that?

Adrienne Farricelli (author) on January 02, 2012:

Millie, you should contact your vet anytime you see side effects. The labored breathing concerns me. Your vet may have to adjust the dosage or change the medication all together. Not much you can do at home, it should wear off with time, but call your vet to play it safe. It may the dosage was too high or she is very sensitive to it.

Millie on January 02, 2012:

My dog is 14 years old, she is a West Highland Terrier. The Vet prescribed her this sedative, however she is not handling it very well. She is having problems with standing, eating, labored breathing and I think she wants to vomit. Also, I think she might have a slight fever and her nose is dry. What should I do to make her better? We are pretty much babying her.

B man on August 11, 2010:

Anybody have any experience with English Bulldogs? Mine is in the hospital right now with a possible blockage problem (surgery). What is the alternative?

Jeff and Ranay on July 15, 2010:

I had a dog we had to sedate every 4th of July. I would contact the Vet a couple a days before and he would give me two pills, only used one but she would injure herself if we did not sedate her. I hated doing it because she would seem to be hung over for two or three days after. I suppose better than her hurting herself though.

Natural Medicine from Midwest USA on November 10, 2009:

Acepromazine is also prescribed for aggressive dogs.

Acepromazine will cause hypotension, decreased respiratory rate, and bracycardia. A sudden collapse, decreased or absent pulse, decreased or absent breathing, pale gums, and unconsiousness may occur in some animals.

Although Acepromazine (Aceproject, PromAce) can cause sedation, a paradoxical reaction of excitement or even severe aggression can occur in some animals. For this reason, dogs under the influence of Acepromazine (Aceproject, PromAce) should be handled gently and should not be left alone with children.

This drug may initiate or worsen epileptic attacks or seizures, and can lower body temperature, allowing for either hypothermia or hyperthermia.

Gypsy Willow from Lake Tahoe Nevada USA , Wales UK and Taupo New Zealand on July 14, 2009:

It helps to know about these things. I may have to take my dog on a long air flight and will probably have to sedate her. Thanks for the information.

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