Cannabinoids for epilepsy: What do we know and where do we go?

Over the past decade there has been an increasing interest in using cannabinoids to treat a range of epilepsy syndromes following reports of some remarkable responses in individual patients. The situation is complicated by the fact that these agents do not appear to work via their attachment to endogenous cannabinoid receptors. Their pharmacokinetics are complex, and bioavailability is variable, resulting in difficulty in developing a suitable formulation for oral delivery. Drug interactions also represent another complication in their everyday use. Nevertheless, recent randomized, placebo-controlled trials with cannabidiol support its efficacy in Dravet and Lennox-Gastaut syndromes. Further placebo-controlled studies are underway in adults with focal epilepsy using cannabidivarin. The many unanswered questions in the use of cannabinoids to treat epileptic seizures are briefly summarized in the conclusion.