Should Physicians Recommend Cannabinoids for Patients with Refractory Seizures?
Darcy Krueger, MD, PhD, and Katherine Holland-Bouley, MD, PhD,discuss the potential and pitfalls of using cannabidiol (CBD)-derived therapies for patients with refractory seizures. Krueger is a pediatric neurologist and director of the Tuberous Sclerosis Clinic at Cincinnati Children’s, and Holland-Bouley is a pediatric epileptologist and co-director of the medical center’s Child Neurophysiology Lab.
What types of CBD-derived therapies are available for patients with refractory seizures?
Holland-Bouley: The U.S. Food and Drug Administration recently approved a new drug called Epidiolex for the treatment of seizures associated with two rare and severe forms of epilepsy, Lennox-Gastaut syndrome and Dravet syndrome, in patients two years of age and older. This is the first FDA-approved drug created from a marijuana derivative, and the first FDA approval of a drug for the treatment of patients with Dravet syndrome.
Epidiolex is not the same as medical marijuana. The active ingredient is 99 percent pure cannabidiol, whereas medical marijuana products contain cannabidiol and hundreds of other chemicals as well. Those chemicals can include tetrahydrocannabinol (THC), which has hallucinogenic properties. Some have advocated that products including CBD combined with THC may be more helpful than those containing CBD alone, especially in conditions associated with chronic pain, but scientific studies supporting these claims are lacking. Currently, the FDA has only approved drugs that contain purified cannabidiol and not THC.
Do CBD-derived therapies have the potential to help patients with other types of seizures?
Krueger: Early research findings are promising, and I think we will begin to see wider applications for cannabinoids. A study published in Epilepsia (Hess et al, 2016) showed that cannabidiol may be an effective and well-tolerated treatment option for patients with refractory seizures associated with tuberous sclerosis complex (TSC). This study paved the way for a full phase III randomized clinical trial, which was conducted by the same company that manufactures Epidiolex. We should see results from that study soon.
What is the downside of using medical marijuana?
Holland-Bouley: Buying medical marijuana is a little like doing business in the Wild West – customers cannot always know exactly what their product contains. And, unlike most FDA-approved drugs, medical marijuana is not covered by insurance.
Krueger: When patients do not respond to medical marijuana products or experience negative side effects, it isn’t possible to make recommendations about dosing or plant selection, because we don’t know the exact composition of these products. Every year the FDA randomly evaluates commercially available natural products that are marketed as containing CBD. In the past three years, the FDA has sent 41 warning letters to firms whose products were found to not contain the levels of CBD they claimed to contain. Being able to prescribe highly regulated, pharmaceutical-grade CBD-derived drugs will help address that problem.
How do you counsel your patients about CBD-derived therapies?
Holland-Bouley: I tell them that CBD-derived drugs hold a lot of promise, but will not work the same for everyone. And I caution them about the variability associated with medical marijuana. Ironically, many families seem to feel more comfortable with using medical marijuana vs. pharmaceuticals, believing that because it is “natural” it will cause fewer side effects. I’m hoping that as the FDA approves more CBD-derived therapies, that perception will change.
Krueger: We still have a lot to learn about the benefits of cannabinoids for seizure control or many other conditions. But the fact is that more than 30 states have legalized medical marijuana, and a growing number of research studies are affirming the benefits of CBD-derived therapies. Patients and families look to their physicians for guidance, so it’s good to be informed and open minded about the potential of these therapies for seizure control and other symptoms when traditional therapies fail to provide relief.
