From Colorado, the Latest on Marijuana for Epilepsy

Andrew N. Wilner, MD; Kelly G. Knupp, MD


February 22, 2016

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Andrew Wilner, MD: This is Dr Andrew Wilner. I'm a neurologist reporting for Medscape. Today I have the pleasure of interviewing Dr Kelly Knupp, a pediatric specialist in epilepsy at the University of Colorado. Welcome, Dr Knupp.

Kelly G. Knupp, MD: Thank you. It's nice to be here.

Dr Wilner: We were both at the American Epilepsy Society meeting in December and I had the opportunity to listen to your talk about marijuana for children with intractable epilepsy. Could you tell me where we are with marijuana in epilepsy? You have a distinct advantage over pretty much any other physician in the United States because marijuana has been legal in Colorado longer than anywhere else. What have you found so far?

Dr Knupp: Overall, we really need more data. We did a retrospective study[1] looking at the use of medical marijuana in our patients and found that about 50% of patients are reporting some improvement. When we dig a little deeper, we see that families who have moved to Colorado to access medical marijuana are more likely to report improvement than our families who already reside here. There is a lot more that we need to understand. Patients are using different products and different doses—but we don't fully understand what the best doses are. In addition, our families here in Colorado are not necessarily using a pharmaceutical-grade product. A lot of our families feel like things change from month to month as they pick up new products. There remains a lot of room for study in these areas.

We have a prospective study[2] that, for the next 3 years, will obtain more definitive information about response rates to medical marijuana. It's an observational study because of legal issues. There is still a discrepancy between what is allowed by the state and what is allowed at the federal level, so we are not allowed to prescribe medical marijuana. Hopefully, this study will provide more data about response rates and side effects related to the use of medical marijuana.

Dr Wilner: I saw a variety of articles regarding potential side effects in the young brain, including depression and even increased incidents of psychosis. As my pediatric neurology colleagues always tell me, the child's brain is different from an adult brain. Is this an area of concern?

Dr Knupp: This is definitely an area of concern and something that warrants more study. Actually, there are groups looking more carefully at medical marijuana in young brains, particularly in animal models. It's an area that has not been very well studied yet. The available studies are in recreational marijuana use and definitely indicate that there is increased concern in the adolescent population compared with the adult population. Those recreational marijuana products may be different from most medical marijuana products because they have different delta-9-tetrahydrocannabinol(THC) contents and different cannabidiol (CBD) contents. This is still an area where we do not really have good answers. In our retrospective study and in the Epidiolex® trials[3] we see a significant rate of side effects in both of these groups. We need to be cautious about side effects and watch for them. [Editor's note: Epidiolex is an investigational plant-derived CBD that has been granted orphan drug status by the US Food and Drug Administration for certain types of epilepsy.]

Dr Wilner: Dr Knupp, thank you for sharing some of your experience with medical marijuana in Colorado. We look forward to the results of your studies. If there are any Medscape viewers who would like to comment, we encourage you. Thanks once again, Dr Knupp, for joining me. I'm Dr Andrew Wilner, reporting for Medscape.


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