Fluoxetine for Separation Anxiety

Canine separation anxiety (SA) is the most frequently reported behavioral disorder after aggression. This study compared the effectiveness and safety of a chewable commercial beef-flavored fluoxetine tablet (Reconcile, Lilly Animal Health) with placebo used in conjunction with a behavior management program for SA. A total of 242 client-owned dogs were randomly assigned to fluoxetine or placebo. Chewable fluoxetine was given at a dosage of 1 to 2 mg/kg once daily. Placebo tablets were identical to the chewable drugs. Owners were called for progress checks after 2 and 6 weeks of treatment, and physical examinations were performed after 4 weeks and at the final visit on week 8. Of the 242 dogs, 197 (101 in the fluoxetine group and 96 in the placebo group) were evaluated. Seventy-two percent of fluoxetine-treated dogs showed improvement in owner-provided overall severity scores (OSSs) for SA behaviors compared with 50% in the placebo group. The weekly rate of decline in OSSs was also significantly more rapid in the fluoxetine group. The frequency of adverse reactions (AEs) was similar in both groups. The most commonly reported AE was "calm/lethargy/depression" and occurred at a significantly higher rate in the fluoxetine group. Most AEs resolved in 1 to 2 weeks. The chewable fluoxetine tablet was concluded to be palatable, well tolerated, and effective for treatment of canine SA. Study funded by Lilly Animal Health, Greenfield, Indiana

COMMENTARY: Separation anxiety is a common behavior problem in veterinary patients. Veterinarians have used pharmaceutical agents, including off-label fluoxetine, for years to treat this condition. It is always helpful to finally have a drug approved for veterinary use. However, the article left me with the following questions and concerns: As with any drug used to aid in behavior modification, how important is the competence and commitment of the owner in adhering to the behavior management program? It is postulated that improvement occurs in treated dogs as a result of increased serotonin levels. Given the time that it normally takes to achieve steady state with this drug, I was surprised at the rapid response reported (1 week), but it may be that improvement (not resolution) does not hinge on steady state for this type of drug. Fluoxetine has side effects-primarily decreased appetite and weight loss and should be used with proper screening and careful monitoring by the veterinarian. However, given the alternative of euthanasia that many of these pets face, this drug may prove useful when used with appropriate behavior management techniques.

Effects of Reconcile (fluoxetine) chewable tablets plus behavior management for canine separation anxiety. Simpson BS, Landsberg GM, Reisner IR, et al. Vet Ther 8:18-31,