Position Statement on the Use of Medical Cannabis for the Treatment of Epilepsy in Canada.

In Canada, recreational use of cannabis was legalized in October 2018. This policy change along with recent publications evaluating the efficacy of cannabis for the medical treatment of epilepsy and media awareness about its use have increased the public interest about this agent. The Canadian League Against Epilepsy Medical Therapeutics Committee, along with a multidisciplinary group of experts and Canadian Epilepsy Alliance representatives, has developed a position statement about the use of medical cannabis for epilepsy. This article addresses the current Canadian legal framework, recent publications about its efficacy and safety profile, and our understanding of the clinical issues that should be considered when contemplating cannabis use for medical purposes.

Énoncé de position quant à l'utilisation du cannabis médical dans le traitement de l'épilepsie. L'utilisation du cannabis à des fins récréatives a été légalisée au Canada en octobre 2018. Parallèlement à ce changement de politique, de récentes publication visant à évaluer l'efficacité du cannabis dans le traitement de l'épilepsie, de même qu'une sensibilisation médiatique accrue en ce qui concerne son utilisation, ont eu pour effet d'augmenter l'intérêt du grand public à son égard. Le Comité médical thérapeutique de la Ligue canadienne contre l'épilepsie (LCCE), de concert avec un groupe multidisciplinaire d'experts et des représentants de l'Alliance canadienne de l'épilepsie, a ainsi élaboré un énoncé de position en ce qui regarde l'utilisation du cannabis médical dans le traitement de l'épilepsie. Cet article entend donc aborder le cadre légal qui prévaut actuellement au Canada et examiner de récentes publications s'étant penchées sur le profil sécuritaire et sur l'efficacité du cannabis. De plus, nous voulons apporter un éclairage au sujet des aspects cliniques dont il faudrait tenir compte au moment d'envisager l'utilisation du cannabis à des fins médicales.

Marijuana: a time-honored but untested treatment for epilepsy.

The biology of the endocannabinoid system in the brain provides a possible basis for a beneficial pharmacological effect of marijuana on seizures. However, evidence for efficacy of cannabis treatment of epilepsy is anecdotal because no acceptable randomized controlled trials have been done. Proper dosage and means of administration remain unknown. Cannabis is safer than other controlled substances, including tobacco or alcohol, and appears to be relatively safe compared with most pharmaceuticals used to treat epilepsy. This is a review of this topic from a Canadian perspective.

Bilateral hippocampal stimulation for intractable temporal lobe epilepsy: impact on seizures and memory.

The effect of continuous electrical stimulation of the hippocampus bilaterally on seizures and memory was assessed in two subjects with seizures from both mesial temporal lobes who were not candidates for resective epilepsy surgery. A double blind, randomized, controlled, cross-over trial design was utilized. Two electrodes with four contacts each were implanted along the axis of the hippocampus bilaterally. Simultaneous stimulation of all electrodes contacts was either on or off during each 3-month interval. Seizure frequency decreased by 33% in the two patients during stimulation and remained lower by 25% for the 3 months after stimulation was turned off before returning to baseline (p < 0.01). No consistent change in objective or subjective measures of memory occurred. No other adverse effects occurred. Seizure frequency is reduced both during and for a period after bilateral hippocampal stimulation, but the overall impact in this study is not as robust as has been previously reported.

Outcome of epilepsy surgery in patients investigated with subdural electrodes.

Invasive intracranial electrodes (IE) are an important part of the work-up in many patients being considered for epilepsy surgery. Because IE are usually reserved for cases where seizure localization is ambiguous, one might expect that the eventual outcome of epilepsy surgery in these patients would be worse than in patients who did not require IE as part of their work-up. The purpose of this study was to specifically examine those patients who underwent insertion of subdural electrodes, to determine how many of these patients eventually underwent resective surgery of any type and to assess the eventual outcome. All cases admitted for subdural electrodes between January 2000 and June 2005 were reviewed. Surgical outcomes were reported using the Engel classification and a multivariate analysis was used to determine which factors were associated with successful surgery. 177 IE implantations were performed in 172 patients. Of these, 130 patients went on to have surgery. In the 113 of the 130 surgical patients in whom 1-year follow-up was available, 47% were seizure free at 1 year. Age was a major predictor of outcome with only 21% of patients over age 40 becoming seizure free with surgery compared to 58% in patients aged under 40 years (p=0.0004). Other predictors of an Engel I outcome included having a temporal lobectomy or supplementary motor area resection. Good results from eventual resective surgery can be achieved in patients needing invasive recordings. Younger patients with temporal lobe epilepsy seem to have the highest likelihood of seizure freedom.

Quality of life after vagus nerve stimulation for intractable epilepsy: is seizure control the only contributing factor?

We assessed the impact of vagus nerve stimulation on a cohort of patients with intractable epilepsy. A 1-year prospective trial of vagus nerve stimulation for intractable epilepsy was done in 26 patients. Seizure frequency, anti-epileptic drugs, and quality of life were assessed using QOLIE-89, ELDQOL, and a Likert scale of impact of treatment. Seizures were reduced by more than 50% in 19% of the patients, by less than 50% in 46%, and were unchanged in 35% of them. Antiepileptic drugs were reduced in 43% of the patients. There was a significant improvement in the mean overall QOLIE-89 score and other measures of quality of life, but these did not correlate with changes in seizure frequency. Subjective improvement occurred in 84% of the patients. The quality of life improves in some patients following vagus nerve stimulation for intractable epilepsy. The favorable effects of this treatment may be attributable to additional factors besides seizure control which in this study was modest.