Cannabidiol Shows Promise in Treating People with Drug-resistant Epilepsy

For approximately one third of people with epilepsy, their seizures cannot be controlled with currently available anti-epileptic drugs (AEDs). Cannabidiol, or CBD, may provide hope for some of these people who have no other treatment option.

Three studies presented at the American Epilepsy Society 70th Annual Meeting looked at the use of CBD for people with Lennox-Gastaut syndrome (LGS) and Dravet syndrome. Dravet syndrome is a rare genetic form of epilepsy that begins in infancy but is lifelong. Most children develop some level of developmental disability and have other conditions that are associated with the syndrome. LGS is associated with multiple types of seizures that persist through childhood and adolescence to adult years. Intellectual development is usually, but not always, impaired.

Lennox-Gastaut Syndrome Study

In a study led by Elizabeth A. Thiele MD, PhD, director of the Pediatric Epilepsy Program at Massachusetts General Hospital, Boston, and professor of neurology at Harvard Medical School, 171 children and adults with LGS received either CBD or a placebo. People were eligible for the clinical trial if they experienced two drop seizures during the baseline week before the study started. They took an average of three AEDs during the study.

After 14 weeks, the study found the following:

• CBD patients experienced a 44% reduction overall in drop seizure frequency compared to a 22% reduction in the placebo group.
• Drop seizures stopped completely for three people in the CBD treatment group.
• 86% of people receiving CBD experienced adverse events versus 69% of people on the placebo.

Adverse events included diarrhea, drowsiness, fever, decreased appetite, and vomiting. Serious adverse effects consisted of abnormal liver function levels, drowsiness, and loss of appetite.

Dravet Syndrome Studies

Helen Cross MB, ChB, PhD, from the University College London, Institute of Child Health, led a study where 120 children were randomly selected to receive either CBD or placebo. Participants in the study had experienced at least four seizures in the 28-day baseline period before the start of the clinical trial. The participant or parents called a dedicated phone number each night to report seizure activity.

The study found the following:

• 39% overall reduction in seizure frequency for CBD patients versus 13% reduction among people on a placebo.
• Seizures stopped completely for 3 people on the CBD treatment.
• 93% of people on CBD experienced adverse events versus 75% of people on a placebo.
• The most common adverse events were drowsiness, diarrhea, decreased appetite, fatigue, fever, vomiting, lethargy, upper respiratory tract infection, and convulsions.
• Serious adverse events included liver function levels, drowsiness, and loss of appetite.

In another study on CBD led by Matthew Wong MD, an epileptologist at the Wake Forest School of Medicine, 34 people with Dravet syndrome were randomly selected to receive CBD or a placebo. This study evaluated dose-ranging safety, tolerability, and pharmacokinetics (the drug’s movement in the body), efficacy, and safety of CBD.

Outlook for the Future

Dr. Thiele, who participated in both the LGS and Dravet studies, said, "For many children with treatment-resistant Dravet syndrome, Lennox-Gastaut syndrome, and other epilepsies, CBD appears to be an effective - sometimes extremely effective-treatment that is safe and well-tolerated overall." She added, "It is not a silver bullet, but there are children who benefit from this more than they have from other treatments."

The CBD studied in these trials was a purified molecule from cannabis that does not include the psychotropic properties of marijuana. It was dispensed in the mouth twice a day but is not available at dispensaries, even in states where medical marijuana is legal. It is expected to be submitted to the U.S Food and Drug Administration for approval as a prescription medicine in 2017.

To learn about CBD and other emerging therapies, visit:

• Accelerating New Therapies
• Advocacy Priorities: Medical Cannabis
• Medical Cannabis: Research and Data

For more information on drug-resistant epilepsy and seizures in children visit:

• About Kids
• Refractory Epilepsy