Epilepsy (Dravet & Lennox-Gastaut)
The strongest evidence of any indication — for purified CBD as add-on therapy in specific rare, treatment-resistant childhood epilepsies.
Last reviewed 15 June 2026 · Education, not medical advice
Supported by high-quality randomised controlled trials for specific situations.
Can medicinal cannabis help with epilepsy in NZ?
Strong evidence for epilepsy. The strongest evidence of any indication — for purified CBD as add-on therapy in specific rare, treatment-resistant childhood epilepsies.There is no fixed list of qualifying conditions in NZ — whether it's appropriate for you is a clinical judgement for a registered doctor. This is education, not a treatment recommendation.
What the evidence says
This is the single strongest RCT evidence in cannabinoid medicine, and it is narrow. In Dravet syndrome, CBD 20 mg/kg/day achieved ≥50% seizure reduction in 43% of patients vs 27% on placebo. In Lennox-Gastaut, median drop-seizure reduction was 43.9% vs 21.8% placebo. Critically, this does NOT generalise to epilepsy broadly — it is established only for these specific syndromes (and tuberous sclerosis), and treatment is neurologist-led. Epidyolex (purified CBD) is one of only two Medsafe-approved cannabis medicines in NZ.
Cannabinoids studied
- CBD
Key cautions
- CBD–clobazam interaction raises the active metabolite ~3-fold (more sedation).
- Hepatotoxicity: ALT >3× upper limit in ~13%, worse with valproate — needs liver-function monitoring.
- Somnolence, decreased appetite and diarrhoea are common.
Sources
Peer-reviewed reviews, trial data and official guidance. We never fabricate figures.
What to do next
If you think medicinal cannabis might help with epilepsy, the next step is a conversation with a registered New Zealand doctor, who can weigh your individual situation. Start with your own GP or a clinic that focuses on cannabis medicine. Our step-by-step pathway walks through the whole process, and our self-check can help you prepare.
This is general information, not medical advice. Only a registered New Zealand doctor can decide whether medicinal cannabis is right for you.
Reviewed for accuracy by the mc.nz editorial team against the cited sources. Last reviewed 15 June 2026.