Acepromazine

Drugbox
IUPAC_name = 1-{10- [3-(dimethylamino)propyl] -10H-phenothiazin-2-yl}ethanone

---

CAS_number=61-00-7
ATC_prefix=N05
ATC_suffix=AA04
ATC_supplemental=
PubChem=6077
DrugBank= DB01614
| C=19 | H=22 | N=2 | O=1 | S=1
molecular_weight = 326.457
bioavailability= 6.6L/kg, high volume of distribution
metabolism =
elimination_half-life= 3 hours in horses
excretion = found in equine urine up to 96 hours after dosage
pregnancy_category =
legal_status = not approved for use in cattle
routes_of_administration= IV, IM, Oral

Acepromazine or Acetylpromazine (More commonly known as ACP, Ace, or by the trade name Atravet or "Acezine 2" etc, number depending on mg/ml dose) is a phenothiazine derivative psychotropic drug. It was first used in humans in the 1950s, [cite journal |author=Collard JF, Maggs R |title=Clinical trial of acepromazine maleate in chronic schizophrenia |journal=British Medical Journal |volume=1 |issue=5085 |pages=1452–4 |year=1958 |month=June |pmid=13536530 |pmc=2029326 |doi= |url=] but is now little used in humans, but frequently in animals as a sedative and antiemetic. Its principal value is in quietening and calming frightened and aggressive animals. The standard pharmaceutical preparation, acepromazine maleate, is used extensively in horses, dogs, and cats; especially as a pre-anesthetic agent often in conjunction with Atropine, and often an opiate such as morphine or buprenorphine. Its potential for cardiac effects can be profound and as such is not recommended for use in geriatric or debilitated animals, (often substituted with midazolam in these cases, or left out of the preanesthetic medication altogether).

Administration

Canine

When used as a premedication it is commonly administered via the subcutaneous route.

Potential adverse effects in dogs

It is thought that acepromazine can potentiate seizures in dogs with epilepsy. However, two recent studies have not shown an association between use of acepromazine and seizure activity, either within 36 hours of acepromazine use [cite journal |author=Tobias KM, Marioni-Henry K, Wagner R |title=A retrospective study on the use of acepromazine maleate in dogs with seizures |journal=Journal of the American Animal Hospital Association |volume=42 |issue=4 |pages=283–9 |year=2006 |pmid=16822767 |doi= |url=http://www.jaaha.org/cgi/pmidlookup?view=long&pmid=16822767] or during hospitalization. [cite journal |author=McConnell J, Kirby R, Rudloff E |title=A retrospective study on the use of acepromazine maleate in dogs with seizures |journal=Journal of Veterinary Emergency and Critical Care|volume=17 |issue=3 |pages=262–7 |year=2007|doi=10.1111/j.1476-4431.2007.00231.x ]

In the Boxer, it has been suggested (on the Veterinary Information Network (VIN), a US-based network for practicing veterinarians) that there is a breed-related sensitivity to acepromazine. This warning was placed in the cardiology section entitled "Acepromazine and Boxers." It described several adverse reactions to acepromazine 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). However, a recent article [cite journal |author=Wagner AE, Wright BD, Hellyer PW |title=Myths and misconceptions in small animal anesthesia |journal=Journal of the American Veterinary Medical Association |volume=223 |issue=10 |pages=283–9 |year=2003|doi=10.2460/javma.2003.223.1426] rebutted this claim, citing references that implicated certain familial lines of Boxers traced back to England. Most Boxers are not adversely affected by acepromazine, though individual dogs of any breed can have a profound reaction characterized by hypotension (low blood pressure).

Acepromazine should be used with caution in sighthounds.

Equine

Acepromazine can be administered by the intramuscular route, taking effect within 30-45 minutes, or may be given intravenously, taking effect within 15 minutes. Sedation usually lasts for 1-4 hours, although some horses may feel the effects for up to 24 hours. The standard dose is highly variable, depending upon the desired effect following administration. An oral gel formulation is also available (Sedalin gel). The dosage by this route is also highly variable, but it is generally accepted that the recommended dose will give moderate sedation in most horses.

In the UK, acepromazine is not authorised for use in horses intended for human consumption. [NOAH, Compendium of Data Sheets for Animal Medicines (2005)] In equine surgery, premedication with acepromazine is has been shown to reduce the perianaesthetic mortality rate, [cite journal |author=GM Johnston, JK Eastment, JLN Wood, PM Taylor |title=The confidential enquiry into perioperative equine fatalities (CEPEF): mortality results of Phases 1 and 2 |journal=Veterinary Anaesthesia and Analgesia |volume=29 |issue=4 |pages=159–70 |year=2002|doi=10.1046/j.1467-2995.2002.00106.x ] although the reasons for this are unclear.

Additionally, acepromazine is used as a vasodilator in the treatment of laminitis, where an oral dose equivalent to "mild sedation" is commonly used, although the dose used is highly dependent on the treating veterinarian. It is also sometimes used to treat a horse experiencing Equine Exertional Rhabdomyolysis.

Precautions when using in horses

Acepromazine is a prohibited class A drug under FEI rules, and its use is prohibited or restricted by many other equestrian organizations. It can be detected in the blood for 72-120 hours, although repeated doses may make it remain present for several months.

Side effects are not common, but the use of acepromazine in stallions is usually considered contraindicated due to the risk of paraphimosis.

Acepromazine should not be used in horses dewormed with piperazine. It lowers blood pressure, and should therefore be used with caution in horses that are experiencing anemia, dehydration, shock, or are colicing.

References