Randomized blinded controlled clinical trial to assess the effect of oral cannabidiol administration in addition to conventional antiepileptic treatment on seizure frequency in dogs with intractable idiopathic epilepsy
McGrath, L. R. Bartner, S. Rao, R. A. Packer, D. L. Gustafson
- Dogs treated with CBD had a significant reduction in seizure frequency, compared with the placebo group
- No adverse behavioral effects were reported by owners
- CBD had no reported proconvulsive effects
- Side effects like somnolence, loss of appetite, and diarrhea were not reported in the present study
OBJECTIVES & HYPOTHESIS → Epilepsy is a chronic condition that causes repeated seizures, and deteriorates the overall well being and quality of life in dogs. Furthermore, it is the most common chronic (long-term) neurological disorder in dogs. To assess the effect of oral cannabidiol (CBD) administration in addition to conventional antiepileptic treatment on seizure frequency in dogs with idiopathic epilepsy.
METHODS → 9 dogs in the CBD group and 7 in the placebo group were included in the analysis. The CBD group received CBD-infused oil (2.5 mg/kg) twice daily for 12 weeks in addition to existing antiepileptic treatments, and the placebo group received non infused oil under the same conditions. Seizure activity, adverse effects, and plasma CBD concentrations were compared between groups.
RESULTS → Dogs in the CBD group had a significant reduction in seizure frequency, compared with the placebo group. Monthly seizure frequency in the CBD group had a 33% decrease (median value before and after study treatment: 4.0 and 2.7, respectively), compared with a reduction of 0% in the placebo group (2.0 and 2.0, respectively). However, the proportion of dogs considered responders to treatment (≥ 50% decrease in seizure activity) was similar between groups with 2 responder dogs in the CBD group, compared with 2 dogs in the placebo group. These not so promising results can be explained by the fact that this was the first study that tested CBD’s effect on epileptic dogs. Therefore, the used dosage was low, since no safety profile was available at the time. Now that more studies about CBD treatment on dogs are available, additional research is warranted to determine whether a higher dosage of CBD would be effective in reducing seizure activity by ≥ 50%.
Moreover, no adverse behavioral effects nor somnolence, loss of appetite, or diarrhea were reported by owners. Despite this safe side effect profile, dogs in the CBD group did have a significant increase in serum alkaline phosphatase (ALP) activity. However without further tests, no clinical implication can be deduced from this value alone.