Interactions Occur With Cannabidiol, Antiepileptic Drugs

Most observed mean level changes fall within accepted therapeutic range

marijuana leaf

TUESDAY, Aug. 8, 2017 (HealthDay News) -- Several significant interactions can occur between cannabidiol and antiepileptic drugs, according to a study published online Aug. 6 in Epilepsia.

Tyler E. Gaston, M.D., from the University of Alabama at Birmingham, and colleagues studied pharmacokinetic interactions between the pharmaceutical formulation of cannabidiol (CBD; Epidiolex; begun at 5 mg/kg/day and increased every two weeks by 5 mg/kg/day up to a maximum of 50 mg/kg/day) and commonly used antiepileptic drugs (AEDs) in an open-label safety study. Serum levels were monitored at baseline before CBD initiation and at study visits. The study participants were 39 adults and 42 children.

The researchers observed significant increases in topiramate, rufinamide, and N-desmethylclobazam and a significant decrease in clobazam serum levels with increasing CBD dose. In adults, there were increases in serum levels of zonisamide and eslicarbazepine with increasing CBD dose. All mean level changes were within the accepted therapeutic range except for clobazam and desmethylclobazam. Higher N-desmethylclobazam levels in adults were associated with more frequent sedation. Aspartate aminotransferase and alanine aminotransferase levels were significantly higher in participants taking concomitant valproate.

"This study emphasizes the importance of monitoring serum AED levels and liver function tests during treatment with CBD," the authors write.

Two authors disclosed financial ties to Greenwich Biosciences, which produces CBD.

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