Archive for the ‘Epilepsy’ Category

Plant-derived cannabinoids (phytocannabinoids) are compounds with emerging therapeutic potential. Early studies suggested that cannabidiol (CBD) has anticonvulsant properties in animal models and reduced seizure frequency in limited human trials. Here, we examine the antiepileptiform and antiseizure potential of CBD using in vitro electrophysiology and an in vivo animal seizure model, respectively. CBD (0.01–100 μM) effects were assessed in vitro using the Mg²⁺-free and 4-aminopyridine (4-AP) models of epileptiform activity in hippocampal brain slices via multielectrode array recordings. In the Mg²⁺-free model, CBD decreased epileptiform local field potential (LFP) burst amplitude [in CA1 and dentate gyrus (DG) regions] and burst duration (in all regions) and increased burst frequency (in all regions). In the 4-AP model, CBD decreased LFP burst amplitude (in CA1 only at 100 μM CBD), burst duration (in CA3 and DG), and burst frequency (in all regions). CBD (1, 10, and 100 mg/kg) effects were also examined in vivo using the pentylenetetrazole model of generalized seizures. CBD (100 mg/kg) exerted clear anticonvulsant effects with significant decreases in incidence of severe seizures and mortality compared with vehicle-treated animals. Finally, CBD acted with only low affinity at cannabinoid CB₁ receptors and displayed no agonist activity in [³⁵S]guanosine 5′-O-(3-thio)triphosphate assays in cortical membranes. These findings suggest that CBD acts, potentially in a CB₁ receptor-independent manner, to inhibit epileptiform activity in vitro and seizure severity in vivo. Thus, we demonstrate the potential of CBD as a novel antiepileptic drug in the unmet clinical need associated with generalized seizures.

by Helen Fields, U.S. News & World Report
December 6th, 2004

Even though there’s not a lot of evidence that it helps, many patients with epilepsy use marijuana, hoping it will reduce their seizures. Researchers in Alberta, Canada, asked epilepsy patients if they were smoking pot.

What the researchers wanted to know: How common is marijuana use among epilepsy patients?

What they did: Patients seen at the University of Alberta Epilepsy Clinic were called and asked about their condition and whether they use medical marijuana.

What they found: Of 136 subjects, 48 (35 percent) had used marijuana in the past month. Nearly half had used it at some time in their lives, and four were determined to be dependent on the drug. People with frequent seizures or who’d had the disease longer were more likely to use marijuana frequently—which could mean that using marijuana makes seizures happen more often but could also mean that patients whose disease was worse were more likely to try alternative treatments. Not surprisingly, people who used other illicit drugs were also more likely to smoke marijuana.

What the study means to you: Many people with epilepsy seem to think marijuana helps. Animal studies have come up with conflicting results—in some, marijuana increases convulsions, while in others it has an anticonvulsant (somewhat more desirable) effect. In any case, if many patients are using marijuana, it seems worth studying more.

Caveats: This is one clinic in Canada, so the findings probably don’t apply to everyone with epilepsy, especially if they live in places with stricter marijuana laws. (Medical use of marijuana is legal in Canada under certain conditions.)

Find out more: The people who run the website the Science of Medical Marijuana are—no surprise—in favor of medical marijuana. They list a few reports and studies: www.medmjscience.org

Go to the National Institute of Neurological Disorders and Stroke for information and resources about epilepsy.

Read the article: Gross, D.W., et al. “Marijuana Use and Epilepsy: Prevalence in Patients of a Tertiary Care Epilepsy Center.” Neurology. June 8, 2004, Vol. 62, No. 11, pp. 2095–2097