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Incidence of seizures associated with the use of acepromazine in dogs undergoing myelography


  • Eleanor A. Drynan BVSc, MACVSc,

    Corresponding author
    • From the Department of Anaesthesia, Murdoch University Veterinary Hospital, Murdoch, Australia.
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  • Peter Gray BVSc, PhD, DVA, DACVA,

  • Anthea L. Raisis PhD, DVA, BVSc, MACVSc

  • Offprints will not be available from the authors.

  • The authors declare no conflict of interest.

  • Partial results were presented as an abstract at the Australian College of Veterinary Scientists Conference July 2008, Gold Coast Australia.

Address correspondence and reprint requests to

Dr. Eleanor Drynan, Department of Anaesthesia Murdoch Veterinary Hospital, Murdoch Drive, Murdoch, WA, 6150.




To investigate the frequency of seizures associated with acepromazine administration when used as a premedicant with methadone for dogs undergoing myelography.


Retrospective clinical case study.


University veterinary teaching hospital.


Sixty-six dogs (mixed and pure breeds), aged between 4 months and 15 years, weighing between 3.5–61 kg. All animals were classified as ASA score I or II.


Forty-three animals were premedicated with methadone (0.1–0.5 mg/kg) and acepromazine (0.01–0.05 mg/kg) intramuscularly. Twenty-three animals were premedicated with methadone alone (0.1–0.5 mg/kg) intramuscularly. Anesthesia was induced with propofol intravenously and maintained with isoflurane delivered in 100% oxygen. All animals received a balanced isotonic crystalloid solution intravenously at a rate of 10 mL/kg/h. Blood pressure, end-tidal CO2, oxygen saturation, respiratory rate, and heart rate were monitored throughout anesthesia. Animals requiring surgery immediately following myelography were excluded from the study.

Measurements and Main Results

The frequency of seizures was 14% (CI: 3.6–24.3%) and 13.0% (CI: 0.7–27%) in dogs that received methadone/acepromazine and methadone alone, respectively. There was no significant difference in the frequency of seizures between dogs receiving methadone/acepromazine or methadone alone (P = 1). Analysis of the association of site of injection of the contrast and the frequency of seizures in dogs receiving methadone/acepromazine showed no significant difference in the frequency of seizures following cervical injection (25%; CI: 0.5–24.5%) or lumbar injection (9.7%; CI: –0.7–20.1%).


The administration of acepromazine combined with methadone as a premedicant used with propofol and isoflurane anesthesia did not significantly increase the frequency of seizures following myelography compared to dogs who received methadone alone.