Trazodone may lessen patient stress while in the veterinary hospital

(Getty Images)Why they did it

The more we know about the detrimental effects of stress in our patients, the more important it is to find ways to minimize stress and improve the welfare of our hospitalized veterinary patients. In this study, the authors evaluate the use of trazodone, a serotonin receptor antagonist and reuptake inhibitor, in mitigating behavioral markers of stress in hospitalized dogs.

What they did

The study authors evaluated stress-related behaviors in 60 dogs ≤ 45 minutes after trazodone administration and again at 90 minutes. For each dog in the treatment group, there was an environmentally matched control dog that was not treated with trazodone (n = 60). Behavioral observations were performed at the same time and by the same person for each pair of dogs. Dogs were excluded from the study if they had received mentation-altering medications (e.g. sedatives) ≤ 2 hours before observation.

For dogs in the treatment group, trazodone was administered starting at 4 mg/kg every 12 hours, which increased to 10 to 12 mg/kg or was administered every eight hours as needed for desired effects. The mean trazodone dose used in the study was 4.65 ± 0.97 mg/kg. The drug was continued for the duration of the hospital stay as needed but did not exceed 300 mg/dose or 600 mg/24 hours.

An observer, blinded to the identification and allocation of each of the dogs, performed 60-second behavioral observations for each dog at the two time points-about 45 and 90 minutes after administration. All paired dogs were housed near each other but could not see the observer during evaluation of the other dog. The observer did not speak to nor did they interact with the dogs at any time during the study.

Behavioral observations were performed at each time point using a behavioral checklist that assessed specific stress-related behaviors. The checklist was used to create an individual behavior score for each dog. The behaviors were also grouped into categories (frenetic, freeze and fractious) to create a behavioral summation score for each dog. The categories intended to describe an individual dog's overall behavior response and to determine if dogs with certain stress-related behaviors would be more likely to benefit from trazodone.

Behavior categories*

Frenetic

Lip licking

Pacing

Panting

Spinning

Trembling

Whining

Yawning

Wet dog shake

Freeze

Averting gaze

Pinning back ears

Whale eye sign

Fractious

Growling

Lunging

Showing teeth

Snapping

*Pupil dilation and lifting of a forelimb were signs that were included in all three categories.

What they found

The authors found that treatment with trazodone resulted in a significant decrease in individual stress-related behaviors including panting, whining and whale eye sign when compared with the control dogs. The drug appeared to be well-tolerated, with only one dog developing signs of aggression after trazodone administration.

The researchers also found that frenetic and freeze summation scores were lower for dogs in the treatment group compared with those in the control group. They noted, however, that frenetic and freeze behavior summation scores were higher in the treatment group to begin with, which may explain why there was a statistically significant decrease in these scores when compared with the control dogs. In addition, they note that a higher proportion of dogs in the control group were evaluated postoperatively, while a higher proportion of dogs in the treatment group were observed preoperatively. The authors suggest that these variables may have affected the dogs' behavior and subsequent behavioral scores as the postoperative dogs had more time to acclimate to their environment.

Take-home message

Trazodone appears to be well-tolerated and may lessen stress-related behaviors in hospitalized dogs. Further studies are warranted to determine the effects of surgical status and duration of hospitalization, as well as to compare effects between groups with comparable baseline behavioral scores.

If in the past you've reached for acepromazine to help calm stressed dogs in the hospital, this study's findings may make you take note. "The standard use of acepromazine, a sedative medication with negligible anxiolytic benefits, in stressed dogs may be detrimental to the behavioral and physical health of those dogs,” write the study authors. For this reason, they recommend that acepromazine not be considered the first choice when managing stress-related behaviors in hospitalized dogs and that trazodone may be considered as an alternative.

Gilbert-Gregory SE, Stull JW, Rice MR, et al. Effects of trazodone on behavioral signs in hospitalized dogs. J Am Vet Med Assoc 2016;249(11):1281-1291.

Link to abstract: http://avmajournals.avma.org/doi/abs/10.2460/javma.249.11.1281

Editors' note: Our thanks to the eagle-eyed reader who found that we had spelled trazodone incorrectly several times throughout this article. We have now updated the article with the correct spelling.