Cumulative Effects of Cannabis Oils on Body Temperature, Electrocardiography, Heart Rate Variability, Blood Pressure,...

Cannabis oils are progressively being investigated as potential treatments for various health conditions in dogs. However, their safety profiles in this species remain poorly understood.

This study evaluated the effects of incremental doses of cannabis oils containing tetrahydrocannabinol (THC), cannabidiol (CBD), and their combination (THC + CBD) on cardiovascular and respiratory parameters in dogs.

Six male Beagles participated in a 3 × 3 crossover study. Acute cumulative doses (1, 2, 4, 8, and 16 mg/kg) were administered via the oromucosal route at 2-h intervals. Measurements included rectal temperature, electrocardiography, heart rate variability, blood pressure, and respiratory plethysmography.

All dogs tolerated the treatments, although adverse clinical signs were observed with THC and THC + CBD, including shivering and vomiting, with THC alone additionally causing ataxia and urinary incontinence. Both THC and THC + CBD caused significant hypothermia starting at a dose of 2 mg/kg, and they also shortened PQ intervals at doses of 4, 8, and 16 mg/kg. THC also significantly prolonged RR and QT intervals at doses of 2, 4, and 8 mg/kg, but not THC + CBD. CBD tended to increase standard deviation of normal RR intervals, root mean square of successive differences, and total power at doses of 8 and 16 mg/kg, while THC and THC + CBD had no significant effect on these parameters. These oils did not produce significant effects on blood pressure or respiratory function within these dose ranges.

CBD oil was well-tolerated, whereas THC and THC + CBD oils induced significant side effects starting at 2 mg/kg. This study establishes a basis for determining appropriate cannabis oil dosages for future clinical studies in dogs.