According to new research, nearly one-third of patients using CBD distillate for seizures develop some level of tolerance to the substance.
The study was conducted by Dr. Shimrit Uliel-Sibony, head of the pediatric epilepsy service at Tel Aviv Sourasky Medical Center’s Dana-Dwek Children’s Hospital in Israel. He presented his findings of “CBD tolerance” to other healthcare professionals at the American Epilepsy Society’s annual meeting in New Orleans last week.
Multiple studies have shown CBD’s effectiveness against seizures, to the extent that the U.S. Food and Drug Administration approved a cannabidiol-based medication – the first ever – to treat two rare and particularly dangerous forms of epilepsy, Lennox-Gastaut syndrome and Dravet syndrome. The drug is called Epidiolex and it’s an oral medication made using CBD distillate and produced by British-based GW Pharmaceuticals.
Foundational studies on Epidiolex followed 92 patients, both children and adults, who had been using Epidiolex regularly for 20 months. About 57% experienced a dramatic reduction in the frequency and severity of their seizures, however, one-third of those patients eventually developed a tolerance that rendered the drug much less effective. All 27 patients who developed a tolerance were prescribed a 30% increased dose. Out of those 27, 12 responded well.
“This is not really a big shock: All the drugs we have and use, even when they work, a year later we’re frequently moving on to the next drug,” said Shlomo Shinnar, president of the American Epilepsy Society and director of both the Comprehensive Epilepsy Management Center at the Montefiore Medical Center and the Albert Einstein College of Medicine in New York City. “This study should temper one’s enthusiasm but it should not eliminate one’s enthusiasm,” he added. “It’s still a good drug. I intend to be using it in my patients.” In the healthcare industry, this is commonly referred to as a drug’s “honeymoon period”. At first, new prescriptions are extremely effective but over time they lose their intensity.
This “honeymoon period” is actually extremely common when it comes to seizure disorders. In many studies, anti-epilepsy medications seemed to lose their intensity much faster than drugs used to fight other classes of diseases. According to Dr. Leah Zachar, “Tolerance has NOTHING to do with the drugs given. It has to do with the pathophysiology, known and (mostly) unknown of seizure disorders.”
She continued to add that “unlike the conventional seizure medications which have side effects that range from bone marrow suppression, to endocrine dysfunction, to gum hyperplasia, CBD has NONE of them. So in other words, if one has a choice between a medicine that may help control their seizures but has a cocktail list of side effects and a medicine that may help to control their seizures with ZERO side effects, the decision of which to take is rather clear. CBD can go toe-to-toe with any other antiepileptic medication on the market today.”
You can’t really argue with that logic. So to summarize, the development of tolerance over time by no means indicates that CBD can’t continue to be an effective, mainstream treatment for epilepsy. It likely has nothing to do with the CBD itself anyway. What it does mean is that it may have to be combined with other medications or supplements in patients who need to use it long-term.
Only time and more studies will be able to paint a larger picture of what is really needed to treat patients with these debilitating forms of epilepsy, but we know that CBD will remain on that list.