Cannabis for Epilepsy and Seizures in Minnesota: A 2026 Guide to CBD, Epidiolex, and Drug Interactions
Approximately 60,000 Minnesotans live with epilepsy, and roughly one in three of them has treatment-resistant seizures -- meaning two or more anti-epileptic drugs (AEDs) have failed to control their condition. For this population, interest in cannabidiol (CBD) is not a wellness trend; it is a clinical question backed by the first cannabis-derived medication ever approved by the U.S. Food and Drug Administration.
This guide covers what the science says about CBD for seizures, why THC is generally avoided in epilepsy management, the critical drug interactions between CBD and commonly prescribed anti-epileptic drugs, how Minnesota's medical cannabis program applies, and how dispensary products compare to prescription-grade Epidiolex.
The Endocannabinoid System and Seizure Biology
A seizure is the result of abnormal, synchronized electrical activity in the brain. The endocannabinoid system (ECS) plays a direct role in regulating neuronal excitability and is now understood to be a key modulator of the brain's ability to suppress runaway electrical activity.
CB1 receptors are densely concentrated in the hippocampus, cortex, and amygdala -- the brain regions most commonly involved in seizure initiation and propagation. Endocannabinoids act as retrograde messengers: when a neuron fires too intensely, it signals neighboring cells via endocannabinoids to dial back activity. Disruption of this system -- including genetic variations in cannabinoid receptors and enzymes -- has been identified in several epilepsy syndromes.
CBD's anticonvulsant mechanisms are distinct from those of THC and are not primarily mediated through CB1 receptor activation. Current evidence points to several pathways: CBD blocks TRPV1 (transient receptor potential vanilloid 1) channels that modulate neurotransmitter release; it antagonizes GPR55, a receptor whose activation is associated with increased seizure susceptibility; it enhances glycine receptor activity, promoting inhibitory signaling; and it indirectly modulates GABA-A receptors. This multi-target mechanism may explain why CBD is effective in seizure syndromes that do not respond to single-mechanism AEDs.
Epidiolex: The FDA-Approved Cannabis Medicine
In June 2018, the FDA approved Epidiolex (pharmaceutical-grade purified CBD) manufactured by GW Pharmaceuticals for two rare, severe childhood epilepsy syndromes: Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS). In 2020, the approved indications were extended to include tuberous sclerosis complex (TSC). Epidiolex is approved for patients one year of age and older and contains no THC.
The approval was based on rigorous randomized controlled trial data:
Dravet syndrome (Devinsky et al. 2017, New England Journal of Medicine): In a landmark trial of 120 children and young adults with Dravet syndrome, CBD reduced convulsive seizure frequency by a median of 39 percent compared with 13 percent in the placebo group. The difference was statistically significant, and 5 percent of CBD patients became completely seizure-free versus 0 percent on placebo. Dravet syndrome is caused by mutations in the SCN1A gene encoding a sodium channel subunit, making it notoriously resistant to most standard AEDs.
Lennox-Gastaut syndrome (Thiele et al. 2018, The Lancet): In a multicenter trial of 225 patients with LGS, the highest CBD dose (20 mg/kg/day) produced a 41 percent median reduction in drop seizures, compared with 14 percent on placebo. LGS is characterized by multiple seizure types, intellectual disability, and abnormal EEG patterns and is one of the most treatment-resistant epilepsy syndromes in pediatric neurology.
Tuberous sclerosis complex: A phase 3 trial in TSC patients showed a 48 percent reduction in focal seizures with CBD versus 26 percent with placebo, leading to the 2020 expanded approval.
These represent the strongest randomized controlled evidence for any cannabis compound in any medical indication -- far more rigorous than the observational evidence available for other conditions like pain, anxiety, or sleep.
THC and Seizures: A Critical Distinction
While CBD has well-documented anticonvulsant properties, THC has a complex and potentially dangerous relationship with seizure threshold. At the molecular level, THC is a partial CB1 agonist. In the hippocampus, CB1 activation can both inhibit and facilitate neurotransmitter release depending on which cell types are targeted. At higher doses, THC can be pro-convulsant in individuals with epilepsy, particularly those with genetic epilepsy syndromes.
Multiple case reports describe new-onset seizures or worsening seizure control in cannabis users, with effects attributable to THC. Patients with Dravet syndrome -- who have sodium channel mutations -- appear particularly sensitive to THC-related seizure destabilization. The American Epilepsy Society's clinical guidance advises neurologists to recommend CBD-only or very-low-THC formulations when cannabis use is under consideration.
For epilepsy management, this means:
- CBD-only products (isolate or broad-spectrum with undetectable THC) are preferred
- 1:1 CBD:THC or high-THC products are generally contraindicated
- Full-spectrum products with trace THC (under 0.3%) may be acceptable in adults, but require discussion with a neurologist
- Smoked or high-dose inhaled cannabis should be avoided
Drug Interactions: What Every AED Patient Needs to Know
This is the most clinically important section of this guide. CBD is a potent inhibitor of several cytochrome P450 and UGT enzymes. Nearly all anti-epileptic drugs are metabolized by these same pathways, making drug interactions between CBD and AEDs both common and clinically significant. Some interactions are dangerous; others are manageable with dose adjustment.
Clobazam (Onfi) -- MAJOR INTERACTION: Clobazam is metabolized to its active metabolite norclobazam by CYP2C19. CBD is a strong inhibitor of CYP2C19. When CBD and clobazam are combined, norclobazam plasma levels rise by approximately three to five times, causing markedly increased sedation, respiratory depression, and central nervous system depression. This interaction is actually one of the reasons Epidiolex appears so effective in LGS patients already taking clobazam -- the elevated norclobazam contributes to seizure control. However, in patients not closely monitored by a neurologist, the combined sedation can be dangerous. Clobazam dose reduction is typically required when adding CBD.
Valproate/Valproic Acid (Depakote, Depakene) -- HEPATOTOXICITY WARNING: CBD inhibits UGT1A9 and UGT2B7, enzymes involved in valproate metabolism. The primary concern is not elevated valproate levels per se, but the increased risk of liver enzyme elevation (AST and ALT) when CBD and valproate are used together. The FDA prescribing information for Epidiolex includes a specific hepatotoxicity warning for this combination. Patients on valproate who add CBD must have liver function tests (LFTs) monitored regularly. Discontinuation of CBD, valproate, or both may be required if elevations occur. Do not start dispensary CBD products if you take valproate without first consulting your neurologist.
Stiripentol (Diacomit) -- DOCUMENTED PHARMACOKINETIC INTERACTION: Per the 2025 FDA prescribing label for Epidiolex, coadministration of CBD at 12.5 mg/kg twice daily increased stiripentol Cmax by 28 percent and AUC by 55 percent. Stiripentol is used in Dravet syndrome, so this interaction is clinically common in that patient population. Stiripentol dose adjustment may be required.
Everolimus (Afinitor, Zortress -- used in TSC) -- SIGNIFICANT INTERACTION: Everolimus is both a CYP3A4 substrate and a P-glycoprotein (P-gp) substrate. CBD inhibits both CYP3A4 and P-gp, potentially causing substantial increases in everolimus plasma levels. Everolimus has a narrow therapeutic window; elevated levels increase the risk of immunosuppression, infections, stomatitis, and pulmonary toxicity. For TSC patients on both everolimus and CBD (Epidiolex is specifically approved for TSC), close therapeutic drug monitoring of everolimus is essential.
Phenytoin/Fosphenytoin (Dilantin, Cerebyx): CBD inhibits CYP2C9, the primary enzyme metabolizing phenytoin. This can raise phenytoin levels, increasing the risk of toxicity (nystagmus, ataxia, cognitive slowing). Phenytoin levels should be monitored when CBD is initiated or dose-adjusted.
Levetiracetam (Keppra, Spritam): Levetiracetam is renally cleared and not significantly metabolized by CYP enzymes. CBD has minimal pharmacokinetic interaction with levetiracetam. This is one of the safest AEDs to combine with CBD from an interaction standpoint.
Lamotrigine (Lamictal): Lamotrigine is primarily glucuronidated by UGT1A4. CBD's inhibitory effect on UGT enzymes creates a theoretical interaction, but clinical evidence for significant lamotrigine level changes with CBD is limited. Monitoring is still advisable when CBD is added.
Topiramate (Topamax): Minor CYP2C19 interaction is possible, but is generally not considered clinically significant at typical CBD doses. The main concern is additive cognitive effects (both CBD and topiramate can impair memory and processing speed).
The overarching message: never add CBD to an existing AED regimen without neurology oversight and baseline liver function testing. The interactions above are manageable, but they require monitoring that over-the-counter dispensary purchases do not provide.
Epidiolex vs. Dispensary CBD: What Is the Difference?
Patients and caregivers often ask whether dispensary CBD -- less expensive and more accessible than a prescription -- can substitute for Epidiolex. The honest answer depends on the severity of the epilepsy and the age of the patient.
Epidiolex advantages:
- Pharmaceutical-grade purity: 100 mg/mL CBD, verified by GMP manufacturing, no contaminants
- Consistent dosing: same concentration batch to batch
- Formal prescribing oversight: a neurologist monitors response, LFTs, and AED interactions
- Insurance coverage: Epidiolex is covered by most state Medicaid programs and many commercial plans under prior authorization
- FDA-approved specifically for Dravet syndrome, LGS, and TSC in children and adults
Dispensary CBD products:
- Variable purity and concentration: certificate of analysis (COA) quality varies by manufacturer
- Less consistent batch-to-batch potency
- No physician monitoring required at point of purchase
- May be an option for adults with mild, partial, or adult-onset seizure disorders who are not candidates for or cannot access Epidiolex
- Significantly lower cost if paying out of pocket (Epidiolex can cost thousands per month without insurance)
For pediatric patients with Dravet syndrome, LGS, or TSC, Epidiolex through a pediatric neurologist is the appropriate path. For adults with treatment-resistant focal seizures who have exhausted multiple AEDs and cannot access Epidiolex, dispensary CBD-dominant products represent a lower-evidence but accessible alternative -- provided a neurologist is involved.
Minnesota Medical Cannabis and Seizure Disorders
Minnesota's medical cannabis program covers seizure disorders as a qualifying condition. Under Minnesota Statute 152.22, epilepsy and seizures are among the conditions for which a healthcare practitioner can certify a patient for the medical cannabis program.
The practical benefits for seizure patients include:
- Exemption from the state cannabis excise tax and state sales tax, saving approximately 22 percent on each purchase
- Access to higher-potency CBD tinctures and formulations that may not be available in the recreational market
- A formal clinical relationship and documentation that supports neurologist coordination
To qualify, your primary care physician or neurologist must certify your condition through the Minnesota Department of Health medical cannabis portal. Read our step-by-step medical card guide or the full list of qualifying conditions for details on enrollment.
Practical Guidance for Epilepsy Patients at Minnesota Dispensaries
If you or a family member with epilepsy is considering dispensary CBD, here is how to approach it safely:
Tell your neurologist first. Given the interactions with clobazam, valproate, phenytoin, stiripentol, and everolimus described above, adding CBD without a neurologist's knowledge creates real risk. Bring a list of current AEDs to any conversation about dispensary products.
Choose CBD-dominant or CBD-only formulations. Ask for broad-spectrum CBD (low/no THC) or CBD isolate products. Avoid 1:1 or high-THC products. Most Minnesota dispensaries stock CBD tinctures -- ask your local dispensary for products with a third-party COA confirming THC content under 0.3 percent or undetectable.
Start with tinctures, not edibles. Tinctures allow precise dose control in milligrams. Edibles have variable absorption and are harder to titrate. Begin at 5 mg CBD per day and increase slowly over several weeks under neurologist guidance.
Keep a seizure diary. Track seizure frequency, type, duration, and CBD dose. A 4-8 week baseline before starting CBD and 8-12 weeks of monitoring after initiation gives meaningful data for you and your neurologist.
Get baseline labs first. Before starting CBD, get a baseline liver function panel (AST, ALT, bilirubin). This is especially important if you take valproate or any other hepatically metabolized AED.
Do not reduce AED doses independently. Even if CBD improves seizure control, do not reduce prescribed AEDs without neurologist guidance. The benefit may partly come from the CBD-AED interaction (as with clobazam), and abrupt AED reduction can precipitate breakthrough seizures.
Frequently Asked Questions
Is epilepsy a qualifying condition for Minnesota's medical cannabis program?
Yes, epilepsy and seizure disorders are qualifying conditions under Minnesota's medical cannabis program. A healthcare practitioner must certify the condition through the Minnesota Department of Health portal. The medical card provides approximately 22 percent savings on cannabis purchases through the combined excise and sales tax exemption.
Can I use dispensary CBD instead of Epidiolex for my child?
Epidiolex is the appropriate choice for children with Dravet syndrome, Lennox-Gastaut syndrome, or tuberous sclerosis complex. It is FDA-approved for these indications, has verified pharmaceutical purity, and is covered by most insurance. Dispensary CBD products have variable quality and are not FDA-approved for pediatric epilepsy. Consult a pediatric neurologist before considering any cannabis product for a child with epilepsy.
Does CBD interact with Keppra (levetiracetam)?
Levetiracetam is renally cleared and not significantly metabolized by CYP enzymes, making it one of the safest anti-epileptic drugs to combine with CBD from a pharmacokinetic standpoint. Some patients on levetiracetam do report increased fatigue or mood effects when adding CBD -- these are pharmacodynamic rather than pharmacokinetic interactions. Still inform your neurologist.
Will CBD affect my Depakote (valproate) levels?
CBD can inhibit the enzymes that clear valproate metabolites, and the combination is associated with increased risk of liver enzyme elevation (ALT/AST). The FDA Epidiolex label includes a specific hepatotoxicity warning for valproate co-use. Do not add CBD to a valproate regimen without baseline liver function tests and regular monitoring by your neurologist.
What dispensary products are best for seizure management?
CBD-only or broad-spectrum CBD tinctures with verified low/no THC are the safest dispensary option for seizure patients. Avoid high-THC products. Ask for a certificate of analysis confirming THC content and CBD concentration. Most Minnesota dispensaries including RISE, Green Goods, Frostbite, and tribal locations carry CBD-dominant tinctures.
Can CBD make seizures worse?
Pharmaceutical-grade CBD at appropriate doses has anticonvulsant effects supported by rigorous trials. However, high-THC cannabis products can be pro-convulsant, especially in patients with Dravet syndrome or other sodium-channel-related epilepsies. Always use CBD-only or very-low-THC formulations, and work with a neurologist who can monitor your seizure diary and EEG.
Is CBD covered by insurance for epilepsy?
Epidiolex (prescription CBD) is covered by most commercial insurance and state Medicaid programs with prior authorization for its approved indications (Dravet syndrome, LGS, TSC). Dispensary CBD is not covered by insurance. Minnesota's medical cannabis card provides a tax exemption (approximately 22 percent savings) on dispensary purchases but does not constitute insurance reimbursement.
