Studying the effects of probiotics for idiopathic epilepsy

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Canine idiopathic epilepsy (IE) is one of the most commonly diagnosed and treated chronic neurological conditions, according to Zoe Bailey, DVM, neurology/neurosurgery resident at the University of Wisconsin-Madison.¹ The cause of this epilepsy type is unknown, but a higher prevalence has been seen in purebred dogs vs mixed breed dogs, and male dogs are more commonly affected than females.²

To treat IE, starting an antiepileptic drug (AED) is the most common route and usually the first line therapy. However, this is not always the best option for every patient and client. Bailey explained in her lecture at the 2024 American College of Veterinary Internal Medicine Forum in Minneapolis, Minnesota, that adverse effects of this medication can negatively impact the client’s perception of their dog’s quality of life. Additionally, approximately 30% of dogs will be drug resistant to this specific treatment.¹ Bailey noted some other therapies for this condition can include dietary changes, use of cannabidiol products, neurostimulation, and more.

Bailey participated in a study aimed at investigating the microbiota-gut-brain axis and its impact on epilepsy. In humans, probiotics have been found to decrease seizure frequency and severity,³ however, there has yet to be a large-scale study on dogs with IE. Bailey and other researchers used a probiotic (Visbiome Vet) with 42-client owned dogs previously diagnosed with IE and already taking a prescription AED. Dogs in this study were between the ages of 1 and 9 years and had a seizure history of at least 6 months, with a frequency of at least 1 every 3 months. “Dogs were enrolled on a rolling basis from January 2022 through May of 2023. So we did a prospective, placebo controlled, masked, crossover clinical trial, both with a 9- or 12-month period, there was a total of 3 or 4 phases, each of which was 3 months in duration,” Bailey explained during the ACVIM session.¹

The first phase was used as an observational period, also to have some control data as a basis before moving forward in the study. The second phase administered a daily placebo capsule provided by Visbiome Vet to the enrolled dogs. A daily dose of the probiotic from Visbiome Vet was given during phase 3 and adjusted based on the dog’s body weight. The study concluded with phase 4 in which dogs were observed again, now evaluating any changes in data with the introduction of a regular dose of probiotics.

By the end of the study, only 21 dogs had completed all 4 phases. “The other 21 dogs were excluded at various time points throughout the study due to the development of new diseases, the need for additional non-AED medications, dietary modifications, owner compliance, and death due to other circumstances,” said Bailey.

Seizure logs were maintained by owners and every seizure was documented. At the start of the study, 17 of the 21 completed dogs were on 2 or more AEDs and 12 of 21 dogs had their AED prescription adjusted by their veterinarian.

The study results revealed the following:

• The mean seizure frequency in phase 1 (observational) was 8.3 seizures per month.
• The mean seizure frequency in phase 2 (placebo) was 8.1 per month.
• The mean seizure frequency in phase 3 (probiotic) was 6.5 per month.

Bailey concluded that, although there was some improvement discovered, the measurement of seizure frequency was not statistically significant enough to prove the use of probiotics improves the outcomes of dogs with IE. Some of the limitations of this particular study was a small population size and reliance on owners for seizure detection and documentation. “So really, the next steps that we're still in progress with are evaluating the microbiome of this population of dogs with refractory idiopathic epilepsy. And then [also] to determine if this biome alters their microbiome,” Bailey said.

References

1. Bailey Z. Effect of a probiotic on seizure frequency in dogs with idiopathic epilepsy receiving anti-epileptic drugs. Presented at: American College of Veterinary Internal Medicine Forum; Minneapolis, MN; June 5, 2024.
2. Canine Idiopathic Epilepsy. University of Missouri Veterinary Health Center. Accessed June 6, 2024. https://vhc.missouri.edu/small-animal-hospital/neurology-neurosurgery/facts-on-neurologic-diseases/canine-idiopathic-epilepsy/
3. Gómez-Eguílaz M, Ramón-Trapero JL, Pérez-Martínez L, Blanco JR. The beneficial effect of probiotics as a supplementary treatment in drug-resistant epilepsy: a pilot study. Benef Microbes. 2018;9(6):875-881. doi:10.3920/BM2018.0018