There is little published research on stress and anxiety in pets during car travel, although transportation has been shown to be stressful for many animals. Acepromazine has been the traditional drug prescribed for cats and dogs requiring sedation, but it has poor anxiolytic activity and produces marked sedation. Anecdotal reports describe tricyclic antidepressants or selective serotonin reuptake inhibitors for use in traveling dogs or cats.  This study sought to document changes in physiologic variables (cortisol, neutrophil-lymphocyte ratio, heart rate) and behaviors observed in dogs during ground transport and to measure whether these variables changed after short-term clomipramine administration. Twenty-four beagles were randomly assigned to clomipramine (2 mg/kg Q 12 H) or placebo groups and were subjected to truck transport on 3 separate occasions, each lasting 1 hour. Tablets were administered 3 days before travel, on the day of travel, and for 3 days after travel to achieve a steady state for clomipramine. Cortisol levels were increased in both groups, although the animals treated with clomipramine had significantly lower levels than the placebo group. The pretransport neutrophil-lymphocyte ratio and the increase after transport were also lower in the clomipramine group, although not significantly. The average heart rate in the clomipramine group was significantly lower than in the placebo group. No significant differences could be detected between treatments for most behavioral data, although clomipramine tended to reduce "moving and panting" and drooling. In addition, the authors noted that the treated dogs appeared calmer than controls. The authors conclude that short-term clomipramine administration appears to slightly reduce fear or anxiety in dogs during transport and may be an appropriate drug choice for this use. Further studies are needed to confirm this finding, as well as to determine appropriate dosage.

COMMENTARY: Owners frequently request medication for pets when taking them on trips. Options until now have been fairly limited: dimenhydrinate (Dramamine) and acepromazine being foremost, neither of which are anxiolytic drugs. This study does a good job of minimizing many variables in an attempt to scientifically confirm anecdotal reports that clomipramine may be another option for travel-anxious pets. While having to give the drug over the course of several days is a drawback, clomipramine would be particularly useful in animals for which dimenhydrinate is insufficient or acepromazine is contraindicated. It would be interesting to see whether further studies show dosing over this length of time is not necessary. In the meantime, clomipramine appears to be a reasonable option to provide comfort for animals that suffer during travel.

Placebo-controlled double-blind clomipramine trial for the treatment of anxiety or fear in beagles during ground transport. Frank D, Gauthier A, Bergeron R. CAN VET J 47:1102-1108, 2006.