The role of cannabinoids and endocannabinoid system in the treatment of epilepsy

Introduction. The treatment of epilepsy is still a major challenge. Despite the introduction of many new antiepileptic drugs, approximately 30% of patients still remain drug resistant. In the absence of a satisfactory therapy outcome, which is sometimes associated with numerous side effects, there is a need for new and effective drugs with low toxicity. Cannabinoids have been shown in preliminary animal model studies and in studies of patients with epilepsy to have antiepileptic activity. Aim. The aim of this paper is to review current reports on the role of the endocannabinoid system and cannabinoids in the treatment of epilepsy. Methods. Articles from PubMed and Scopus published up to 2015 concerning the role of cannabinoids and the endocannabinoid system in the treatment of epilepsy are reviewed. Review and Discussion. Cannabis has been used for thousands of years in the treatment of various diseases. They contain cannabinoids, which act on the endocannabinoid system which regulates many biochemical and physiological processes. By affecting glutamate and gamma-aminobutyric acid (GABA) neurotransmission cannabinoids have the ability to affect seizure threshold. The best known cannabinoid is cannabidiol, which inhibits the occurrence of seizures without causing significant side effects in humans and animals. However, only a small number of double blind, randomized and placebo controlled studies have been published to date. Conclusions. The role of cannabinoids in the treatment of epilepsy is not well defined because these substances have shown pro-convulsive actions in some animal studies and also there are not many randomized trials performed to date. The existing human data do not support the conclusion that cannabinoids are effective and safe in the treatment of epilepsy, but do encourage further studies on a larger group of patients.