Cannabis and CBD for Epilepsy in Switzerland: What the Evidence Shows

A sober guide to cannabis, CBD and epilepsy: what the Epidyolex trials show, pharmaceutical CBD vs retail oil, interactions with antiepileptics, THC risks, and the Swiss route via neurology and insurance.

Epilepsy is the only condition for which a cannabinoid is an approved prescription medicine: Epidyolex, a highly purified CBD product, holds Swissmedic approval for severe childhood epilepsy syndromes. At the same time, few areas carry as much misinformation — from miracle claims to scaremongering. This guide separates the two: what the pivotal trials actually show, why shop-bought CBD oil and Epidyolex are not interchangeable, where self-experimentation becomes dangerous, and how the Swiss route through neurology, prescription and insurance works.

Understanding epilepsy: why there is no "one treatment for all"

Epilepsy is not a single disease but an umbrella term for very different disturbances of the brain's electrical activity. There are focal seizures starting in one brain region and generalised seizures involving both hemispheres — absences, myoclonic and tonic-clonic seizures. Behind them stand genetic syndromes, brain injuries, metabolic diseases or simply no identifiable cause.

About two thirds of patients become seizure-free on conventional antiepileptics. The remaining third has treatment-resistant epilepsy — seizures persist despite a correct diagnosis and at least two well-tolerated antiepileptic drugs. This is precisely the group where cannabinoid research is most serious, and precisely where the Epidyolex approval is anchored. Someone with a mild, well-controlled epilepsy is not the target group — and anyone adding THC products gives their brain a variable no neurologist can cleanly interpret.

What the approval trials actually show

The robust data come from randomised, placebo-controlled trials of pharmaceutical cannabidiol in three severe epilepsy syndromes:

• Dravet syndrome: a rare, severe genetic epilepsy beginning in the first year of life. In the trials, convulsive seizure frequency under CBD fell significantly more than under placebo.
• Lennox-Gastaut syndrome: a severe childhood epilepsy with several seizure types. Drop attacks — the seizures carrying fall risk — showed particularly relevant reductions.
• Tuberous sclerosis complex (TSC): in this genetic condition with frequent epilepsy, CBD also reduced seizure frequency significantly more than placebo.

The honest reading matters: the trials never aimed at cure and rarely at seizure freedom, but at a reduction in seizure frequency of 50 percent or more. Depending on the trial, about a third to almost half of patients reached that mark — a major difference for families facing daily seizures, but not a miracle for the average patient. For the common adult forms, such as focal epilepsy, comparable approval trials are still missing.

Epidyolex in Switzerland: approval, prescription, reality

Epidyolex is an oral cannabidiol solution (100 mg/ml) without a meaningful THC content, approved in Switzerland by Swissmedic. The approval is narrow: as add-on therapy for the three named syndromes, generally from age two. It is prescribed by neurology and paediatric neurology — not as a lifestyle product.

In practice the treatment follows a strict titration schedule: starting dose, stepwise increases over weeks, a weight-based target range, with liver enzyme checks in between. That is not red tape — it is the core of the concept. Trial doses sit at 10 to 25 mg per kilogram of body weight per day, orders of magnitude beyond what drops from a shop can reach — let alone monitor.

Pharmaceutical CBD vs shop CBD: why these are not synonyms

Anyone "experimenting" with retail CBD for epilepsy is combining three unknowns: unclear dose, unclear residual THC and no monitoring. In a condition where every seizure can mean injury, that is the wrong place for improvisation. How to verify a product's quality at all is covered in reading a lab report; for systematic CBD dosing outside the medical setting see the CBD dosage guide.

Interactions: the most critical section of this guide

CBD inhibits liver enzymes, above all CYP2C19 and CYP3A4 — the very systems through which many antiepileptics are metabolised. The most important interaction in practice:

• Clobazam: CBD markedly raises the level of its active metabolite — more sedation, more side effects. This was the most frequent relevant interaction in the trials.
• Valproate: the combination with CBD led to elevated liver enzymes more often in trials — which is why regular liver checks are part of the Epidyolex treatment plan.
• Other antiepileptics (topiramate, stiripentol, zonisamide and others): blood levels can shift — individually, not predictably across the board.

Consequence: with epilepsy you never start or stop CBD on your own — not even "just an oil". The neurology team must know what is being added so blood levels and liver values can be monitored. The mechanism is explained in cannabis interactions with medication.

THC and epilepsy: why extra caution applies

For THC the evidence is uncomfortably thin — and uncomfortably ambivalent. Animal data show both anticonvulsant and proconvulsant effects depending on model and dose. For people with epilepsy, three concrete risks come on top:

• Situational seizure triggers: sleep deprivation, stress and alcohol — classic epilepsy triggers — frequently accompany recreational use.
• Withdrawal seizures: daily high-THC use followed by stopping brings a withdrawal phase with disturbed sleep and excitability — a genuine problem in epilepsy. Background in tolerance and T-breaks.
• Untested products: fluctuating potency makes any self-observation worthless. The cannabinoid differences are explained in CBD vs THC.

There is no evidence that high-THC cannabis improves epilepsy — and there is a documented mechanism by which it can worsen control. That is the order that matters.

The Swiss route: neurology, prior approval, everyday life

The medical path is clear: diagnosis and treatment trials run through the GP and a neurological epilepsy clinic. If Epidyolex is indicated, the physician prescribes it; for off-label consideration in other epilepsy forms, the insurer decides case by case via prior approval. The process is covered in cannabis prescriptions in Switzerland, and reimbursement questions in medical cannabis and health insurance.

Two everyday topics deserve honest answers. Driving licence: in Switzerland, people with epilepsy need a defined seizure-free period for the licence — usually one year on stable therapy, assessed case by case by traffic medicine. THC use is doubly problematic here: medically for fitness to drive, legally because of the road-traffic limit — details in cannabis and driving. And documentation: a seizure diary (date, duration, triggers, medication changes) is the single most effective tool — it turns feeling into data a neurologist can work with.

What this means for the club

We do not treat epilepsy, and no club product is a medicine. What we can offer on this topic is the same honesty as everywhere else: lab-tested batches, declared values, no healing promises. Anyone with epilepsy considering CBD belongs in neurology, not in self-experimentation — and anyone comparing products anyway should at least know how to read a lab report and what a certificate is worth. General adverse effects are summarised in cannabis side effects.