By Wendy Wallner, DVM

There is one drug commonly used in anesthetic protocols that should not be used in the Boxer. The drug is Acepromazine, a tranquilizer, which is
often used as a preanesthetic agent. In the Boxer, it tends to cause a problem called first degree heart block, a potentially serious arrhythmia of
the heart. It also causes a profound hypotension (severe lowering of the blood pressure) in many Boxers that receive the drug.


Recently, on the Veterinary Information Network, a computer network for practicing veterinarians, an announcement was placed in the cardiology section entitled “Acepromazine and Boxers.” This described several adverse reactions to the drug in a very short time span at a veterinary teaching hospital. All the adverse reactions were in Boxers. The reactions included collapse, respiratory arrest, and profound bradycardia (slow heart rate, less than 60 beats per minute). The announcement suggested that Acepromazine should not be used in dogs of the Boxer breed because of a breed related sensitivity to the drug.


This drug is the most commonly prescribed tranquilizer in veterinary medicine. It is also used orally and is prescribed for owners who want to tranquilize their dogs for air or car travel. I would strongly recommend that Boxer owners avoid the use of this drug, especially when the dog will be unattended and/or unable to receive emergency medical care if it is needed.

Acepromazine and Boxers

By Rachel Tennant, DVM, MS

Acepromazine (ACE) is a sedative that is commonly used in veterinary medicine. From as early as the mid 1990’s, there have been warnings posted on the internet about this drug in regards to its use in Boxers. Reactions are reported to range from profound and extended sedation, arrhythmias, bradycardia (low heart rate), and/or severe hypotension (low blood pressure).


While there have been no official studies, there are many anecdotal reports from both pet owners and veterinarians in regards to use of this drug. One theory is that sensitivity to ACE is more common in Boxers of UK and Canadian bloodlines, but others report incidences in the US. Without a way to determine which animals are sensitive, we cannot be sure if or when a Boxer may have a reaction to this drug.

Previously, Plumb’s Veterinary Drug Handbook carried the following warning:

“Prolonged effects of the drug may be seen in older animals. Giant breeds, as well as greyhounds, appear quite sensitive to the clinical effects of the drug, yet terrier breeds appear more resistant. Boxer dogs, on the other hand, are predisposed to hypotensive and bradycardic effects of the drug.”

This warning, however, has been removed from current editions; therefore your veterinarian may not be able to reference it.

Recommendation: Avoid Acepromazine

I recommend trying to avoid the use of this drug in Boxers, especially if they are going to be unattended or unable to get to emergency care if needed. This recommendation was also made by Dr. Wendy Wallner, a well-known Boxer veterinarian. Fortunately, there are many other drug choices available, and a safe protocol can be designed to avoid this drug if there is concern.

This drug is used to premedicate prior to surgery, as well as sent home for sedation post surgically or for travel. If you are in any way uncomfortable with the use of ACE in your Boxer, please let your veterinarian know. It is your dog, therefore your choice. Your veterinarian should respect your decision in regards to your companion.

Personally, as a Boxer owner and a vet, I choose to avoid this drug in Boxers. The potential risk is not worth it when there are many other options available.