Medical Cannabis for Epilepsy: CBD Evidence and Doses
CBD is the only cannabis compound with FDA approval for epilepsy. Epidiolex treats Dravet, Lennox-Gastaut, and tuberous sclerosis. THC has no approval.
Answer First
Medical cannabis dosing for epilepsy uses weight-based CBD. The only FDA-approved cannabis-derived drug is Epidiolex, a CBD oral solution. It starts at 2.5 mg/kg twice daily. The dose rises over weeks. THC has no established dose for epilepsy. Some patients take CBD-rich products without FDA approval. Those products vary in strength and purity.
FDA-Approved CBD Dosing
Epidiolex is approved for seizures linked to Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex. The oral solution contains 100 mg of CBD per mL.
- Starting dose: 2.5 mg/kg twice daily (5 mg/kg/day).
- After 1 week: 5 mg/kg twice daily (10 mg/kg/day).
- Maximum for Lennox-Gastaut and Dravet: 10 mg/kg twice daily (20 mg/kg/day).
- Maximum for tuberous sclerosis complex: 12.5 mg/kg twice daily (25 mg/kg/day).
Example: a 20 kg child starts at 50 mg twice daily. The same child at the 10 mg/kg twice daily dose takes 200 mg twice daily.
medical cannabis for epilepsy dosage
Dose changes occur at weekly intervals. Some clinicians titrate at a slower pace. The target dose depends on seizure control and side effects.
medical cannabis for epilepsy dosage
THC and Epilepsy
THC is not approved for epilepsy in the US. Clinical trials of THC for seizures are small. A common investigational mix is CBD to THC at a 1:1 ratio. One trial used 2.5 mg/kg/day of CBD plus THC. Results were mixed. THC can trigger seizures in some patients. No standard THC dose exists for epilepsy.
Drug Interactions
CBD changes how the liver breaks down other drugs. Key interactions include:
- Clobazam: CBD raises the active metabolite norclobazam. This can cause sedation.
- Valproate: CBD plus valproate can raise liver enzyme levels.
- Stiripentol, everolimus, and rufinamide: CBD may change blood levels.
Doctors adjust doses of these drugs when CBD is added.
Monitoring
Liver enzymes (ALT, AST) are checked at baseline, 1 month, 3 months, 6 months, and then at intervals. A rise above 3 times the upper limit of normal calls for a CBD dose reduction or stop. Sedation, diarrhea, and appetite loss are common side effects.
Over-the-Counter CBD Products
Hemp-derived CBD products are not FDA-approved for epilepsy. Studies find that many labels list incorrect CBD and THC amounts. Third-party lab tests show actual content. A product with 0 mg THC differs from one with 5 mg THC per mL.
Unknowns
The best dose for each patient is found by trial. Long-term effects on child development are not fully known. Data on THC for epilepsy remain weak. Talk to a neurologist before starting any cannabis product.