Acepromazine and Boxers
This is a collection of references from various veterinary publications which discuss the increased sensitivity of Boxers to acepromazine. This is in no way a complete list.
This is an e-mail discussion between veterinarians around the world regarding the problems with acepromazine and Boxers:
Acepromazine may cause syncope in brachycephalic breeds. Boxers are reportedly very sensitive to the hypotensive and bradycardiac effects of acepromazine and even small doses should be used cautiously in this breed.
Psychopharmacology of Animal Behavior Disorders
Nicholas H. Dodman, Louis Schuster
Giant breeds and greyhounds may be extremely sensitive to the drug, while terrier breeds are somewhat resistant to its effects. Boxers are reported to be very sensitive to the hypotensive and bradycardiac effects of acepromazine....
Veterinary Drug Handbook
Third Edition, 1999
Donald C. Plumb
Adverse [effects]: Hypotension, penile paralysis (equine), decreased seizure threshold, prolonged duration with liver diseas; anecdotal reports of profound respiratory and cardiovascular depression in Boxers.
Janyce L. Cornick-Seahorn
Fainting and cardiovascular collapse has been reported to occur occasionally in all species of animal following the use of even low doses of acepromazine. In some cases it may have been due to administration to a hypovolaemic animal but in others it has not been explained. Some strains of Boxers are known for collapsing after a very small dose of acepromazine given by any route, and it has been suggested that this may be due to orthostatic hypotension or to vasovagal syncope.
Tenth Edition, 2001
L.W. Hall, K.W. Clarke, C.M. Trim
Phenothiazines such as acepromazine should be used with caution in Greyhounds and other coursing hounds and in brachycephalic breeds. In the Boxer in particular fainting may be precipitated.
The Veterinary Formulary
Yolande M. Bishop, British Veterinary Association
Acepromazine can cause syncope associated with high vagal tone and subsequent bradycardia; this occurs in brachycephalic breeds, particularly in Boxers.
Veterinary Pharmacology & Therapeutics
Eighth Edition, 2001
H. Richard Adams
What is meant by 'boxer sensitivity to acepromazine' or 'boxer-ace syndrome'? What could be the factors influencing its occurrence?
The administration of acepromazine to some boxers can induce profound bradycardia, associated with hypotension and collapse of the animal. This is a dramatic event experienced by a generation of veterinary clinicians, especially in the United Kingdom. Some clinicians report that doses as low as 0.01 mg/kg given subcutaneously have induced collapse in an otherwise healthy animal. It appears to be related to certain strains of the breed. An explanation for this problem such as excessive vagal response or epinephrine reversal has not been documented.
Veterinary Anesthesia and Pain Management Secrets
Stephen A. Greene
Some Boxers have demonstrated pronounced side effects and have even died after administration of acepromazine as an adjuvant to opioid analgesia.
Handbook of Veterinary Pain Management
James S. Gaynor, William Muir
Fainting associated with high levels of vagal tone (sometimes termed vasovagal syncope) has been described in brachycephalic breeds, particularly boxers, given acepromazine. In these cases collapse is associated with bradycardia and treatment involves the administration of an anticholinergic druce such as atropine.
Small Animal Clinical Pharmacology
Jill E. Maddison, Stephen W. Page, David Church
Boxers are known to be unduly susceptible to ACP [acepromazine], and occasionally respond to the drug by collapsing with profound hypotension and bradycardia.
Anaesthesia for Veterinary Nurses
Disadvantages:....Syncope: some breed-lines of Boxers collapse after low doses.
Third Edition, 2004
D.R. Lane, B. Cooper
Boxers are prone to vasovagal syncope with acepromazine and should receive an anticholinergic if acepromazine is used. Alternatively, it should be avoided.
Veterinary Dentistry for the General Practitioner
Acepromazine is safe in healthy young adult animals, but should be avoided in patients with a known seizure history, liver disease, heart disease, geriatric or pediatric patients, any dehydrated animal, and Boxers.
Shelter Medicine for Veterinarians and Staff
Lila Miller, Stephen Zawistowski
Boxers are very sensitive to the effects of acepromazine; use with caution at very low dose rates.
Clinical Procedures in Veterinary Nursing
Giant breeds, as well as greyhounds, appear quite sensitive to the clinical effects of the drug, yet terrier breeds appear more resistant. Conversely, boxer dogs are predisposed to the hypotensive and bradycardiac effects of the drug.
Handbook of Veterinary Drugs
Third Edition, 2004
D.G. Allen, J.K. Pringle, D.A. Smith with K. Pasloske and K. Day
There are medical contraindications for ACP, including epilepsy, brachycephalic breeds, history of respiratory depression, hepatic dysfunction, renal compromise and hypotension.
Behaviour Problems in Small Animals
John Bowen, Sarah Heath
Acepromazine should not be used in patients with a history of seizures and should be used with caution in young or debilitated animals, geriatric patients, pregnant females, giant breeds, greyhounds, and boxers.
Sharon L. Crowell-Davis, Thomas Murray
The side-effects of short term use of acepromazine include the following (Booth, 1988; Dodman,1998):
Hypotension (often accompanied by a compensatory tachycardia)
Syncope, particularly in brachycephalic breeds, the Boxer being especially sensitive
Currently posted on the website of the South African Veterinary Council.
In some dogs, particularly Boxers and other short-nosed breeds, spontaneous fainting or syncope may occur, due to sinoatrial block caused by excessive vagal tone, and an attack may be precipitated by acepromazine
This is a direct quote from the Novartis product insert, and is currently posted on both of these websites:
Veterinary Medicines Directorate (UK; government agency of the Department for Environment, Food and Rural Affairs). (Word document)
National Office of Animal Health (UK)