THC Intoxication by Cannabidiol-Enriched Cannabis Extract in Two Children with Refractory Epilepsy

Δ9-THC Intoxication by Cannabidiol-Enriched Cannabis Extract in Two Children with Refractory Epilepsy: Full Remission after Switching to Purified Cannabidiol

José A. S. Crippa1*, Ana C. S. Crippa2, Jaime E. C. Hallak1, Rocio Martín-Santos1,3and Antonio W. Zuardi1

  • 1Department of Neuroscience and Behavior, University of São Paulo, Ribeirão Preto, Brazil
  • 2Department of Clinical Medicine, Federal University of Paraná, Curitiba, Brazil
  • 3Institute of Neuroscience, Hospital Clinic, August Pi i Sunyer Biomedical Research Institute – Center for Biomedical Research in Mental Health Network and Department of Medicine – University of Barcelona, Barcelona, Spain

Animal studies and preliminary clinical trials have shown that cannabidiol (CBD)-enriched extracts may have beneficial effects for children with treatment-resistant epilepsy. However, these compounds are not yet registered as medicines by regulatory agencies. We describe the cases of two children with treatment-resistant epilepsy (Case A with left frontal dysplasia and Case B with Dravet Syndrome) with initial symptom improvement after the introduction of CBD extracts followed by seizure worsening after a short time. The children presented typical signs of intoxication by Δ9-THC (inappropriate laughter, ataxia, reduced attention, and eye redness) after using a CBD-enriched extract. The extract was replaced by the same dose of purified CBD with no Δ9-THC in both cases, which led to improvement in intoxication signs and seizure remission. These cases support pre-clinical and preliminary clinical evidence suggesting that CBD may be effective for some patients with epilepsy. Moreover, the cases highlight the need for randomized clinical trials using high-quality and reliable substances to ascertain the safety and efficacy of cannabinoids as medicines.

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