Drugs, dogs, and driving: the potential for year-round thermal stress in UK vehicles.

Background: Dogs are regularly transported or housed in vehicles, with guidelines for housing dogs suggesting that the ambient temperature should be maintained between 15°C and 24°C. Veterinary drugs are routinely stored and carried in vehicles providing ambulatory veterinary care. Non-refrigerated medications typically require storage between 8°C and 25°C. Aim: This study aims to investigate the potential for thermal stress associated with vehicular storage and transportation of drugs and dogs in a temperate climate, such as the United Kingdom. Methods: The study used data loggers to continuously record internal temperatures of four vehicles at 15-minute intervals over a two-year period, to investigate the effect of seasonality and time of day on the internal car temperature. Results: The internal car temperature ranged from -7.4°C to 54.5°C during the study period. Temperatures fell below 8°C every month, except June and July. The internal car temperature exceeded typical drug storage recommendations (>25°C) during every month, and exceeded the canine thermoneutral zone (>35°C) from April to September. Peak temperatures occurred between 14:00 and 17:00 hours. Conclusion: The results demonstrate the year-round potential for thermal stress of both dogs and drugs left in cars. Public awareness campaigns highlighting the risks of leaving dogs in hot cars are typically launched in late spring, but should consider launching earlier in light of these findings. Veterinary surgeons transporting drugs should take measures to ensure that drugs are stored within the manufacturer's temperature range year-round. This will limit the potential for drug degradation and decreased efficacy.