Acepromazine for or in Seizures?

Some phenothiazines reportedly reduce the seizure threshold and induce electroencephalography (EEG) discharge patterns like those seen in epilepsy. Acepromazine has, therefore, generally been avoided in dogs with histories of seizures, although the effects of acepromazine in these animals have not been well documented. This retrospective study evaluated the response of dogs with seizures to acepromazine. Medical records revealed 36 dogs with histories of seizures that had been given acepromazine for tranquilization during hospital stays and 11 dogs in which acepromazine was given to decrease seizure activity. In the 36 dogs given acepromazine for tranquilization, no seizures were seen within 16 hours of administering the drug. Eight of the 10 dogs that were given acepromazine to decrease seizure activity showed abatement of seizures for 1.5 to 8 hours (n = 6) or their seizures did not recur (n = 2). One dog had a reduction in excitement-induced seizure frequency for a period of 2 months. While no evidence indicated that acepromazine increased the risk for seizures in dogs with seizure histories, several factors confounded the evaluation of drug effects in this study, including variation in the cause of disease and drug dosage; concurrent administration of sedatives, anesthetics, or anticonvulsant medications; and the retrospective nature of the study. A prospective study is probably necessary to determine the true incidence of seizures after acepromazine administration in dogs with seizure histories and in the general canine population.

COMMENTARY: This is a useful article that discusses pertinent evidence on the effects of acepromazine maleate on seizure threshold. Many veterinarians still use acepromazine in patients with seizure disorders, and according to this study, some have even used it to directly treat seizures. Unfortunately, the evidence of this study is not much stronger than the original evidence that made us wary of using acepromazine in patients that have seizure disorders in the first place. The article is worth reading to know the situations in which acepromazine was used. From the information presented, selective use of acepromazine in certain patients is reasonable.

A retrospective study on the use of acepromazine maleate in dogs with seizures. Tobias KM, Marioni-Henry K, Wagner R. JAAHA 42:283-289, 2006.