The use of trazodone to facilitate calm behavior after elective orthopedic surgery in dogs: Results and lessons learned from a clinical trial

Trazodone hydrochloride is an atypical antidepressant that has entered clinical use for dogs and cats for a variety of indications. These include management of anxiety disorders, facilitation of travel and veterinary examinations, and facilitation of calm behavior in hospitalized and postoperative patients. Despite the increasingly common use of trazodone in dogs, very little literature exists evaluating trazodone's efficacy against a placebo control. The aim of the study reported here was to evaluate trazodone in a randomized placebo-controlled clinical trial for use in facilitating calmness and ease of confinement in postoperative dogs. The study enrolled 29 dogs (14 in the trazodone group and 15 in the placebo group) and followed them during 4 postoperative weeks. Trazodone was well tolerated by dogs in the trazodone group. Although dogs in both groups were rated as improved on some behavioral measures, no difference was found between the trazodone and placebo groups in efficacy, with more than 70% of owners in both groups rating the test article (trazodone or placebo) as moderately or extremely helpful for facilitating both calming and crating of their dog. This observed lack of efficacy, over placebo, may be attributed to one or more of several factors that include features about the trial itself and the trial population, a caregiver or placebo-by-proxy effect, a lack of sensitive outcome measures for assessment, or a lack of true efficacy for the medication. It is concluded that future work will be needed to address these factors, and this report aims to provide not only results but lessons learned from the conduct of the described trial.