How is CBD used in the treatment of epilepsy?

'Medical cannabis' refers to any medicine derived from the cannabis plant. This plant contains hundreds of natural compounds, but the two most important in medical treatments are cannabidiol (CBD) and tetrahydrocannabinol (THC). CBD is one of several chemical compounds found in the cannabis plant. Unlike delta-9-tetrahydrocannabinol (delta-9 THC), another well-known cannabis compound, CBD does not induce psychoactive effects; the ‘high’ often associated with cannabis. Typically, CBD is extracted from the hemp plant, which contains minimal amounts of THC.¹ However, aside from the prescription medication Epidiolex, over-the-counter CBD products are not FDA-approved. This lack of approval means no federal standards are in place to ensure their content, purity, or potency. Currently, the UK Epidiolex is the only cannabis-based drug approved for the treatment of epilepsy. This drug contains pure CBD, with no THC, and is available through the NHS for specific types of epilepsy.

For those who experience seizures or are caring for someone who does, managing them with as few side effects as possible is a top priority. CBD oil has gained significant attention as a potential treatment for epilepsy as it offers a promising option for reducing seizure frequency and severity in certain cases. CBD, short for cannabidiol, is a compound found in marijuana. Although many claims about CBD remain untested, scientific support for its ability to reduce pain, anxiety, and seizures is growing. Clinical trials have shown that CBD can significantly reduce seizures in people with specific forms of epilepsy, such as Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex.² There are also early indications that CBD may help manage other types of seizures or enhance the effectiveness of traditional antiepileptic medications. Clinical trials have demonstrated significant reductions in seizure frequency for patients with these conditions, marking a pivotal development in epilepsy treatment options. Early clinical trials also indicate that CBD may be effective for individuals with other epilepsy types, enhancing the use of traditional antiepileptic medications. 

Is CBD safe?

Despite its growing popularity, many questions about the safety of CBD, particularly for over-the-counter products, remain unanswered. While pharmaceutical-grade CBD has undergone rigorous clinical trials, many products available to the public lack such thorough testing. Over-the-counter CBD products often contain unreliable amounts of the compound and may also be contaminated with harmful substances, such as pesticides or heavy metals. Additionally, CBD may interact with other medications, potentially affecting liver function, particularly at high doses. Given these risks, it is essential to consult a healthcare provider before starting CBD, especially for individuals taking other medications or with underlying health conditions.

While early results suggest that CBD is a promising treatment for epilepsy, particularly in drug-resistant cases, several long-term concerns require careful consideration. Most studies focus on short-to-mid-term outcomes, raising questions about the long-term safety of CBD. Although some trials extend treatment periods to a year, the effects of prolonged high-dose CBD use (up to 50 mg/kg/day) necessitate further investigation. Continuous monitoring for potential side effects, particularly regarding cognitive function and overall health, is critical for ensuring patient safety.

Use in specific epilepsy types

Many studies focus on particular forms of epilepsy, such as TSC, West Syndrome, and Sturge-Weber Syndrome. The outcomes of these trials will help ascertain whether CBD is equally effective across different epilepsy syndromes or if its use needs tailoring to specific conditions. Overall, these trials aim to enhance the treatment options available for epilepsy by identifying the safest and most effective ways to incorporate CBD into patient care. However, ongoing concerns about long-term safety, efficacy, and potential drug interactions will continue to shape future guidelines regarding CBD's use in managing epilepsy.³

Evidence from clinical trials

Numerous studies have explored CBD's efficacy in treating epilepsy, particularly in rare conditions. For instance, early clinical trials showed that CBD could dramatically reduce seizures in patients with CDKL5 deficiency disorder, Aicardi syndrome, Doose syndrome, and Dup15q syndrome. Notably, these trials found that CBD maintained its efficacy throughout the trial period, suggesting potential long-term benefits for individuals with epilepsy.

A significant aspect of these studies is their focus on varying patient populations, from infants to young adults, assessing CBD’s use as an adjunct therapy to standard antiepileptic drugs (AEDs). Trials often employ a gradual dose escalation method to identify the most effective dose while minimising adverse effects, with dosages ranging from 2 mg/kg/day to as high as 50 mg/kg/day.⁴

Safety and efficacy assessments

Key areas of focus in these clinical trials include:

Safety and tolerability

Early-phase trials aim to identify safe dosing levels for CBD, monitoring patients for any side effects or adverse interactions with other AEDs. These studies provide crucial data on how well patients tolerate varying doses of CBD, which will inform future treatment protocols.

Efficacy

Later-phase trials are dedicated to evaluating whether CBD can effectively reduce seizure frequency. This is a critical metric in determining its utility for managing epilepsy. Trials specifically targeting conditions like tuberous sclerosis complex and infantile spasms use seizure frequency as a primary outcome measure, aiming to demonstrate significant improvements with CBD administration.

Drug-drug interactions

Several studies investigate how CBD interacts with commonly prescribed AEDs, such as stiripentol and valproate. Understanding these interactions is vital for patients who rely on multiple medications to manage their epilepsy effectively.

Long-term outcomes

Some trials involve extended treatment periods, often spanning a year or longer. This aspect is crucial for assessing the prolonged effects of CBD on seizure management and overall patient health. Monitoring these patients over time helps gather data on both the efficacy and any emerging concerns, such as cognitive side effects, changes in sleep quality, or adverse reactions.

Potential side effects of CBD⁵

As the popularity of cannabidiol (CBD) grows, particularly for managing health conditions, it is essential to understand the potential harms, side effects, and unknowns associated with its long-term use. A survey conducted in 2019 indicated that 14% of American adults had used CBD products, a figure that surged to one in three adults by 2020. Despite the increasing availability of CBD, significant concerns about its safety, effectiveness, and the quality of over-the-counter products remain prevalent.

Key concerns with CBD products

Inconsistent quality and safety

 Many CBD products fail to deliver the advertised CBD amounts and may contain harmful contaminants, including excess THC. Research shows only 31% of CBD products are accurately labelled, with significant health risks for children. A study revealed that 21.4% of samples contained unlabeled delta-9 THC, and some hemp oils exceeded the legal THC limit of 0.3%. This can result in users testing positive for marijuana, even at low THC levels. Misleading labelling can lead to employment issues, inaccurate medical results, legal complications, and unexpected drug interactions. The FDA prohibits CBD from being marketed as a dietary supplement or added to food and beverages.

Potential side effects 

While CBD is generally considered safe, it can cause side effects such as drowsiness, mood changes like irritability and agitation, loss of appetite, and gastrointestinal distress (e.g. diarrhoea). In some cases, CBD may also impact liver function or interact negatively with other medications, raising the risk of severe health issues.

Misleading labels

Some items advertised as CBD may have higher levels of THC than suggested, which could lead to risks such as failing employment drug tests or experiencing unforeseen interactions with other medications.

This highlights the importance of pursuing NHS prescriptions for CBD products if you are considering this option for treating epilepsy and seizures. Doing so ensures that you are using quality-controlled and safe products for yourself or your loved ones.

Summary

Cannabidiol (CBD) has emerged as a promising treatment for drug-resistant epilepsy, showing potential to significantly reduce seizure frequency and enhance quality of life. However, concerns about long-term safety, efficacy, and possible drug interactions necessitate careful consideration. As research progresses, healthcare providers and patients must navigate the complexities surrounding CBD. Ongoing clinical trials and observational studies will clarify its role in epilepsy management and aid in tailoring treatment approaches. 

Despite promising initial findings, current research has limitations, including small sample sizes and short trial durations, which complicate assessments of long-term effects. Much of the existing research focuses on specific epilepsy types, limiting the generalisability of results. While CBD has demonstrated potential in the short term, its long-term effectiveness remains uncertain. Extended trials are essential to determine whether patients develop tolerance or if benefits persist without additional side effects. 

Moreover, further research is needed to evaluate CBD's efficacy across a wider range of epilepsy syndromes, particularly in children. Longitudinal studies will provide critical insights into the chronic effects of CBD on cognitive function and overall health. Given that many epilepsy patients are on multiple antiepileptic drugs (AEDs), the risk of drug interactions is a significant concern. CBD may alter the efficacy of these medications, highlighting the importance of careful dose adjustments and monitoring.⁶

FAQs⁷

What types of seizures is CBD effective for?

CBD has been shown to be effective for certain types of seizures, particularly those associated with Lennox-Gastaut syndrome and Dravet syndrome. Epidiolex, the only FDA-approved CBD medication, specifically targets these conditions, but ongoing research continues to explore its effectiveness for other seizure types.

Are there any age restrictions for using CBD for seizures?

Epidiolex is approved for use in patients aged two years and older. While there is some evidence supporting the use of CBD in children and adolescents with epilepsy, it’s essential to consult with a healthcare professional for personalised recommendations and to monitor for potential side effects.

How long does it take to see the effects of CBD on seizures?

Patients may start to notice the effects of CBD within one to two weeks of starting treatment, but it can vary based on individual response and dosage. It's crucial to work with a healthcare provider to monitor progress and make necessary adjustments.

Can CBD be used alongside other alternative therapies for epilepsy?

Yes, CBD can be used alongside other therapies, such as dietary interventions (e.g., ketogenic diet) or herbal supplements. However, it's important to discuss any alternative therapies with a healthcare professional to ensure they are safe and appropriate for your treatment plan.

What should I do if I experience side effects from CBD?

If you experience side effects from CBD, such as increased drowsiness or mood changes, consult your healthcare provider. They can help assess whether to adjust the dosage or consider alternative treatment options. It’s essential to report any severe or concerning side effects immediately.