CBD showed powerful synergistic effects when combined with neurosteroids or benzodiazepines against treatment-resistant focal seizures in adult mice.
Epilepsy researchers, neurologists treating refractory seizures, and pharmacologists studying drug combinations.
0.164 combination indexfor CBD plus midazolam, indicating strong synergism for seizure protection
What the researchers found
CBD combined with ganaxolone or midazolam produced combination indices of 0.313 and 0.164 respectively, indicating strong synergism for seizure protection with little to no toxicity.
Why it matters
Over one-third of epilepsy patients have drug-resistant seizures. This study suggests CBD could enhance existing medications rather than replace them, potentially offering new treatment strategies for adult refractory epilepsy.
The numbers in context
CBD alone had an ED50 of 53 mg/kg. Combination index for CBD+ganaxolone was 0.313 and CBD+midazolam was 0.164, both indicating strong synergism. Three standard ratios were tested (1:1, 1:3, 3:1).
How the study worked
Preclinical study using the adult 6-Hz model of focal refractory epilepsy in mice. CBD was tested alone (dose-response and time-course) and in isobolographic combination with ganaxolone and midazolam.
Who was studied
Adult mice in a 6-Hz model of focal refractory epilepsy, with both sexes examined.
What this study cannot tell us
Animal model results may not translate directly to humans. The 6-Hz model, while validated, represents only one type of refractory epilepsy. Doses used in mice may not correspond to human dosing.
How to read the evidence
Preclinical animal study with rigorous isobolographic analysis, but results require human clinical validation.
When this study was published
Recent preclinical research contributing to an expanding body of evidence on CBD for epilepsy.
The bigger picture
While CBD is approved for pediatric epilepsies like Dravet and Lennox-Gastaut syndromes, this research expands its potential to adult refractory focal epilepsy, particularly as combination therapy with existing GABAergic medications.
Replication
Preclinical findings; human clinical trials needed to confirm translational relevance.
Funding
Not specified in abstract
Conflicts of interest
Not specified in abstract
Questions still open
- Will these synergistic effects translate to human clinical trials?
- What are the optimal dose ratios for CBD combinations in clinical settings?
Read the original research
Isobolographic analysis of adjunct antiseizure activity of the FDA-approved cannabidiol with neurosteroids and benzodiazepines in adult refractory focal onset epilepsy.
Experimental neurology, 360, 114294
Citation
Golub, Victoria; Ramakrishnan, Sreevidhya; Reddy, Doodipala Samba. (2023). Isobolographic analysis of adjunct antiseizure activity of the FDA-approved cannabidiol with neurosteroids and benzodiazepines in adult refractory focal onset epilepsy.. Experimental neurology, 360, 114294. https://doi.org/10.1016/j.expneurol.2022.114294