Cannabidiol is the major nonpsychoactive ingredient in cannabis. Cannabidiol demonstrates a range of effects that may be therapeutically useful, including anti-seizure, antioxidant, neuroprotective, anti-inflammatory, analgesic, anti-tumor, anti-psychotic, and anti-anxiety properties. Exact mechanism of action of cannabidiol is not known, but may include effects on the orphan G-protein-coupled receptor GPR55; the transient receptor potential of vanilloid type-1 channel; the 5-HT1a receptor; and the α3 glycine receptors. GW Pharmaceuticals successfully developed the world’s first prescription medicine derived from the cannabis plant, Sativex® (buccal spray containing delta-9-tetrahydrocannabinol and cannabidiol) now approved in over 29 countries outside of the United States for the treatment of spasticity due to Multiple Sclerosis. GW Pharmaceuticals is developing Epidiolex® (a liquid formulation of pure plant-derived cannabidiol) for certain rare and severe early-onset, drug-resistant epilepsy syndromes.

Clobazam belongs to the 1,5-benzodiazepine class of drugs with antiepileptic properties. It has been used to treat anxiety and epilepsy since 1970s. In the US clobazam was approved for marketing in October of 2011 for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome. It is also approved for adjunctive therapy for epilepsy in patients who have not responded to first-line drugs and in children who are refractory to first-line drugs. The mechanism of action for clobazam is not fully understood but is thought to involve what is known as potentiation of GABAergic neurotransmission resulting from binding at a benzodiazepine site at the GABA(A) receptor. Possible side effects: constipation, fever, drowsiness, sedation, ataxia, aggressive behavior, lethargy, drooling, and irritability. Other side effects include: urinary tract infection, pneumonia, cough, dysphagia, dysarthria, bronchitis, insomnia, fatigue, decreased appetite, and increased appetite.

Rufinamide is an anti-epileptic drug that is FDA approved for the treatment of lennox-gastaut syndrome (LGS). The principal mechanism of action of rufinamide is modulation of the activity of sodium channels and, in particular, prolongation of the inactive state of the channel. Hormonal contraceptives may be less effective with rufinamide. Patients on valproate should begin at a rufinamide dose lower than 10 mg/kg per day (pediatric patients) or 400 mg per day (adults). Common adverse reactions include headache, dizziness, fatigue, somnolence, and nausea.

Cinromide possesses antiepileptic activity in various animal models. However, in the experiments for human, this drug had a very limited clinical usefulness and was withdrawn from testing by its manufacturer. The lack of an antiepileptic response may have been due to factors other than species differences but indicates that a positive result of a drug in animal models is not the sole factor necessary to predict beneficial antiepileptic activity in humans. In addition, cinromide was studied for the patients with Lennox-Gastaut Syndrome, as a result, there was no difference between cinromide and placebo in terms of seizure reduction or global evaluations.