Study: Effects of Trazodone Compared to Acepromazine in Anesthetic Induction

Acepromazine is frequently used for pre-medication before veterinary visits and surgery. While it offers sedation, it doesn’t offer any substantial anxiety relief. The authors of a study published in the February 2017 issue of the Journal of the American Veterinary Medical Association investigated the use of trazodone instead of acepromazine as an oral pre-medication.

Thirty healthy, client-owned dogs were admitted for tibial plateau leveling osteotomy or tibial tuberosity advancement and assigned to one of two groups: acepromazine or trazodone.

The acepromazine group received 0.01 to 0.03 mg/kg IM 30 minutes before anesthetic induction, and the trazodone group received 5 mg/kg for patients > 10 kg or 7 mg/kg for patients ≤ 10 kg, PO 2 hours before induction.

Both groups received morphine sulfate (1 mg/kg IM) 30 minutes before induction. Anesthesia was induced with propofol (4 to 6 mg/kg IV) and maintained with isoflurane or sevoflurane in oxygen. Bupivacaine (0.5 mg/kg) and morphine (0.1 mg/kg) were administered epidurally.

Findings included:

  • There was no difference in the mean dose of propofol and all cardiovascular variables between groups.
  • No significant differences were seen in the cardiovascular effects of premedication that included acepromazine versus trazodone.
  • No significant differences were seen in the mean propofol dose needed for induction, mean isoflurane vaporizer setting, mean duration of anesthesia, or median surgical time between the treatment groups.
  • Heart rates and blood pressure measurements were the same for all dogs.
  • Both groups had similar numbers of dogs who required intervention for low blood pressure and bradycardia.

In her evaluation of the study, boarded veterinary behaviorist Dr. Lisa Radosta of the Fear Free Executive Council said:

This study shows that there is an opportunity to use a medication with more anxiolytic and fear-reducing properties than acepromazine with no significant differences in outcome. Veterinarians can now ask clients to pre-medicate with trazodone at home so that pets will be calmer when they enter the clinic and ideally be less stressed and fearful as well as easier to handle.

Murphy LA, Barletta M, Graham LF, Reichl LJ, Duxbury MM, Quandt JE. Effects of acepromazine and trazodone on anesthetic induction dose of propofol and cardiovascular variables in dogs undergoing general anesthesia for orthopedic surgery. J Am Vet Med Assoc. 2017 Feb 15;250(4):408-416. doi: 10.2460/javma.250.4.408.