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The long‐term efficacy of cannabidiol in the treatment of refractory epilepsy
Author(s) -
Patel Sandip,
Grinspoon Reid,
Fleming Bradley,
Skirvin Lauren A.,
Wade Christina,
Wolper Emma,
Bruno Patricia L.,
Thiele Elizabeth A.
Publication year - 2021
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/epi.16936
Subject(s) - cannabidiol , concomitant , medicine , epilepsy , refractory (planetary science) , adverse effect , adjunctive treatment , drug resistant epilepsy , diarrhea , retrospective cohort study , pediatrics , lennox–gastaut syndrome , anesthesia , cannabis , psychiatry , physics , astrobiology
Objective Cannabidiol (CBD) has been shown to reduce seizures among patients with refractory epilepsies of various etiologies in recent clinical trials and an expanded access program (EAP). Most studies report efficacy over short time periods (<1 year), with little published on longer term efficacy. Here, we investigate the efficacy of CBD for a treatment period of up to 60 months (median = 45.5 months). Methods We conducted a retrospective review of patient‐reported seizure logs and medical records for 54 subjects with refractory epilepsy who enrolled in the Massachusetts General Hospital's open‐label EAP for CBD as a new treatment for epilepsy. We analyzed the effect of CBD on seizure frequencies and concomitant antiepileptic drug (AED) use at 1 year after starting treatment and the most recent study visit. Results Our results indicate that CBD maintains its efficacy for controlling seizures from Year 1 to the most recent study visit. The percentage of seizure responders remained similar at these time points (41.7%–42.6%), and the seizure response rate was also maintained ( p = .12). Efficacy was also seen over a broad dose range, and up to 50 mg/kg/day. CBD was particularly effective for controlling seizures in the setting of tuberous sclerosis complex and for reducing epileptic spasms and absence seizures. Although CBD use did not lead to an overall decrease in concomitant AEDs, most subjects reduced the dose of at least one concomitant AED compared to baseline. CBD was generally well tolerated, with drowsiness and diarrhea as the primary adverse reactions. Significance This study demonstrates CBD does not lose its efficacy in controlling seizures over a treatment period of up to 60 months. Taken alongside other results on the efficacy and tolerability of CBD in the treatment of refractory epilepsies, our results provide evidence that CBD is an effective, safe, and well‐tolerated AED for long‐term use.