Adults only (18+)

This article examines whether cannabidiol (CBD) has the potential to reduce the frequency of seizures. It is written for people living with epilepsy or seizure disorders, their families and carers, as well as health care professionals seeking an uptodate, UKcentred review of the evidence, regulation and practical considerations around CBD use in this context. The aim is to present clear, balanced information based on current UK sources, to help informed discussion rather than to promote use.

Understanding the topic: what is CBD and how might it relate to seizures

Cannabidiol, commonly known as CBD, is a nonpsychoactive compound found in the cannabis plant. Unlike tetrahydrocannabinol (THC), CBD does not cause the high typically associated with cannabis. In recent years it has received increasing attention for its potential use in a variety of health related contexts, including seizure disorders. In the UK, the only cannabis based medicine licensed for epilepsy is a highly purified formulation of CBD, known as Epidyolex, which is authorised as an adjunctive therapy for certain severe epilepsy syndromes.

The logic behind using CBD for seizures is tied to its action on the endocannabinoid system and other neuronal pathways, which might influence neuronal excitability and the threshold for seizures. Research in specific epilepsy syndromes has shown reductions in seizure frequency when CBD is used as an add on to standard antiepileptic drugs. However the key caveats relate to the fact that this evidence is limited to specific syndromes and formulations under medical supervision.

Who might consider CBD for seizure reduction

In the UK the approved use of CBD for seizures is restricted. Epidyolex is available only for people with severe, treatment resistant epilepsy syndromes such as Dravet syndrome or Lennox Gastaut syndrome or for seizures associated with Tuberous sclerosis complex when two or more standard antiepileptic medications have already failed to achieve adequate control.

That means that for the majority of people living with epilepsy, particularly more common or less severe forms, CBD is not currently a standard routine treatment. It is viewed as an adjunctive option in a specialist context. The typical user in this scenario is someone who has tried and not achieved satisfactory results with conventional treatments and whose neurologist or epilepsy specialist considers CBD appropriate and manages the process carefully.

Summary of the evidence base: what we know about CBD and seizures

When reviewing whether CBD reduces seizure frequency the crucial points are the amount and quality of evidence and how applicable that is to different types of epilepsy.

Research has produced randomised controlled trials for CBD in Dravet and Lennox Gastaut syndromes. For instance, one study in children with Dravet syndrome found that add on CBD reduced the frequency of convulsive seizures significantly compared to placebo. In another for TSC associated seizures, a Phase III trial reported that CBD at 25 mg per kilogram per day achieved a median seizure reduction of 49 per cent versus 27 per cent in the placebo arm over 28 days.

On the other hand, the UK’s National Institute for Health and Care Excellence evidence review noted that there were only four parallel randomised trials for severe treatment resistant epilepsy and the quality of evidence was very low to low. The committee concluded they could not make broad recommendations for CBD outside the specified syndromes.

In practice this means that for certain rare, severe syndromes, CBD has been shown to reduce seizure frequency in a clinically meaningful way when used under medical supervision and alongside other drugs. But the evidence does not yet extend robustly to the full range of epilepsy types or to over the counter CBD products.

How much reduction can be expected and what are the limitations

In the trials referenced above, reductions in seizure frequency of around 30 to 50 per cent compared to placebo have been observed for some participants. For example in the TSC study the treated group showed a 49 per cent median reduction versus 27 per cent in placebo, giving a difference of about 22 percentage points in reduction. That suggests that for some people the benefit is significant yet not everyone achieves seizure freedom and some will respond less well or not at all.

Important limitations are that in many trials the duration of controlled observation was relatively short, for example 16 weeks or so in the TSC trial. Longer term outcomes such as neurodevelopment in children, learning disabilities, status epilepticus risk or sudden death reduction remain less well characterised.

Another limitation is applicability. The majority of evidence is in children and young people with specific syndromes rather than adults or other kinds of epilepsy. Unlike standard antiepileptic drug treatments for which there is broad evidence, CBD remains essentially a specialist add on for defined circumstances. NICE emphasised that because of the differences in underlying pathologies between types of epilepsy the results from Dravet or Lennox Gastaut may not translate to other syndromes.

Finally, there is a need for monitoring and tight medical oversight given potential drug interactions, liver enzyme elevations, and the importance of prescribing a pharmaceutically produced standard product rather than unregulated supplement type CBD. Guidance from the British Paediatric Neurology Association stipulates that CBD should not replace standard antiepileptic medication and is best considered as add on therapy.

Regulation, safety and quality: UK specific context

In the UK any product claiming to treat or prevent a disease must be authorised as a medicine. The only CBD product with a licence for epilepsy is Epidyolex. That means most CBD oils or capsules bought from health food stores or online, while legal under some circumstances and subject to food supplement regulation, are not authorised medicines and are not approved for seizure reduction or epilepsy treatment. Epilepsy Action states clearly that non medical CBD products should not be seen as a substitute for prescribed epilepsy medicine.

From a safety monitoring perspective, NICE recommends baseline liver function tests, regular monitoring after dose increments and assessment of drug interactions.

The UK guideline for cannabis based medicinal products states that these should only be prescribed where the benefits outweigh potential risks for patients who have exhausted standard treatments.

Patients and caregivers must work with a specialist who understands epilepsy, drug interactions and the specific epilepsy syndrome being treated. Any self medication or substitution of standard treatment with non licensed CBD carries risks of uncontrolled seizures, interactions and use of products of varied quality.

Feature overview: what does CBD treatment involve in this context

When used in the epilepsy syndromes described above, CBD is used as an adjunctive therapy; that is, added alongside standard antiepileptic medicines rather than replacing them. The dosing in trials has varied by body weight, for example starting at 5 mg per kilogram per day and increasing up to 25 mg per kilogram per day or more under specialist supervision.

Treatment typically involves pre treatment assessment including liver function, review of current antiepileptic medications and baseline seizure frequency to allow monitoring of response and side effects. Once prescribed, seizures and side effects are monitored frequently and if no meaningful improvement is observed after a defined period then the medicine may be withdrawn.

From a practical standpoint the formulation is a pharmaceutical oral solution manufactured to Good Manufacturing Practice standards. The user experience is quite different from over the counter CBD oil. The specialist prescribing team will coordinate with pharmacy, neurology and epilepsy nursing to adjust doses, monitor labs and review seizures.

Pros and cons: weighing the advantages and the caution points

One of the advantages of CBD in this context is that for selected patients with treatment resistant epilepsy it offers another option when standard treatments have failed. The clinical trials suggest that it may reduce the frequency of high impact seizures and thereby may improve quality of life for children and families in those specific circumstances. The use of a defined licensed product under specialist supervision reduces many of the risks associated with unregulated products.

On the other hand the limitations must be emphasised strongly. It is not a guarantee of seizure freedom and may not work for all. It requires close monitoring, may involve adding to complex drug regimens with risk of interactions, and the evidence base outside the rare syndromes remains weak. For many people with more common types of epilepsy there is simply insufficient evidence that CBD will reduce seizure frequency. Also, self medicating with over the counter CBD in the hope of reducing seizures is risky; the variability in product quality, unknown dosages, presence of THC or contaminants, and the potential to reduce uptake of standard antiepileptic drugs are real concerns.

Comparison and alternative options

In standard epilepsy management, first line treatments remain conventional antiepileptic drugs chosen for the specific seizure type, epilepsy syndrome, age and comorbidities. Other options might include ketogenic diet, epilepsy surgery, vagus nerve stimulation or other neuromodulation therapies, depending on individual case assessment. The introduction of CBD for seizure reduction should be viewed as part of this broader armamentarium rather than a standalone natural alternative. CBD is recommended only when conventional therapies have been unsuccessful.

Flavour, experience and practicalities from the patient and carer perspective

Although flavour and taste are less relevant in the epilepsy prescription context compared to consumer CBD oils, from a user experience perspective the key elements are ease of administration, monitoring burden and realistic expectation setting. The oral solution is non inhaled and is designed for precise dosing rather than flavour appeal. While a health food shop CBD oil might be taken more casually and for potential general wellness, in the seizure context the experience is rigorous, medical, and involves frequent check ins, dose titrations, blood tests and seizure diary recording. Patients and families often cite improvements in the number of seizure free days and reduced unpredictability as meaningful. For many families dealing with severe syndromes the ability to reduce drop seizures or reduce days with seizures can allow greater confidence in daily life, school attendance and participation in activities.

It is important to remember that the treatment is not feel good or self care in the casual sense but a medical therapy with monitoring requirements, potential side effects and cost implications. Any perceived improvement must be discussed with the specialist and seizure diaries need to be maintained accurately.

Common questions and misconceptions

One common question is whether over the counter CBD oil can be used to reduce seizures. The answer is no, not reliably. While such products may contain CBD, they are not authorised medicines, their potency, contents and quality are not sufficiently regulated for seizure treatment application in the UK. Epilepsy Action warns against assuming that high street or online CBD products are safe or effective for epilepsy.

Another misconception is that CBD will cure epilepsy or eliminate seizures altogether. The evidence shows reduction in frequency for selected patients but does not guarantee seizure freedom. Families and patients must maintain realistic expectations. Also the idea that natural means safe is false in this context. CBD interacts with other medications, has side effects such as liver enzyme changes and sedation and requires specialist oversight.

People sometimes assume that CBD is a first line therapy for seizures but guidance clearly places it as a later option after conventional treatments have been tried. The British Paediatric Neurology Association stresses that CBD should be used when standard therapies have failed and evidence in children and young people is limited outside the specified syndromes.

Another practical question concerns when any new treatment should be stopped if not effective. In children and young people with epilepsy if after four months there is no significant reduction then withdrawing the CBD may be appropriate.

Practical steps if you are considering CBD for seizures

If you or a family member have epilepsy and are thinking about CBD, the first step is to speak with your epilepsy specialist or neurologist. It is vital to ensure full evaluation of your epilepsy syndrome, past treatments, seizure patterns, comorbidities and concurrent medications. If your specialist considers CBD appropriate, you would typically be prescribed a licensed formulation such as Epidyolex, and the process would include baseline investigations including liver function, careful dose titration, seizure diary recording, and frequent follow up.

You should be aware that this is a therapy reserved for specific situations in the UK and not all epilepsy types are eligible. Over the counter CBD products should not be used as a substitute for prescribed epilepsy care. Keeping accurate records of seizure occurrences, side effects, and communicating any changes to your specialist team is essential.

Conclusion

In summary, there is clear evidence that in certain rare and severe epilepsy syndromes, properly prescribed and monitored cannabidiol in the licensed formulation can reduce the frequency of seizures when used alongside standard treatments. The reductions seen in trials are meaningful for many patients, improving quality of life and providing an additional therapeutic option. However, the evidence is limited to defined syndromes, not all epilepsy types, and use outside those contexts is not supported by robust data. Quality control, specialist supervision and realistic expectations are central to safe and effective use.

If you are considering CBD for seizure reduction it is crucial to talk to your epilepsy specialist, follow the prescribed medical pathway, and not rely on non licensed products. More research is ongoing and it is likely that future years may broaden our understanding of CBD’s role in epilepsy. But at present the message for UK audiences is one of cautious optimism in specific circumstances, not general endorsement for all seizure types or over the counter use.