By Heidi Moawad, MD  Medically reviewed by Claudia Chaves, MD 
Updated on January 14, 2020

Cannabidiol (CBD)—a component of the marijuana plant—has gotten a lot of attention for medical use, including the treatment of epilepsy. Epidiolex is the only prescription form of CBD available, and it was approved by the U.S. Food and Drug Administration (FDA) in June 2018 for the treatment of seizures in two hard-to-treat forms epilepsy—Lennox-Gastaut syndrome (LGS) and Dravet syndrome.1

 Epidiolex is approved for adults and children over the age of 2 who have one of these rare disorders.

How It Works

Seizures are caused by erratic electrical activity in the brain that can spread and cause uncontrolled physical movements and/or alterations of consciousness. Most anti-seizure drugs work by slowing down excitatory nerve activity in the brain.

However, LGS and Dravet syndrome may be treated with medications that aren't commonly used for most types of epilepsy. Additionally, they often require two or more anti-seizure drugs for seizures to be under control.

It is not completely clear why CBD can reduce some types of seizures. It is known to have a range of biochemical effects on nerve cells in the brain, some of which may have an impact on seizures. Medical research on CBD is still in its early stages.

Indications

Prescription CBD is specifically recommended for control of seizures in LGS and Dravet syndrome.

LGS is a developmental disorder that begins in early childhood and is characterized by multiple seizure types, as well as physical and cognitive deficits. The seizures of LGS are difficult to control and are managed with a different medication regimen than that which is used for most epilepsy types.

Dravet syndrome is a developmental disorder that begins in early childhood and is associated with multiple seizure types as well as seizures triggered by fevers. People with Dravet syndrome often have behavioral challenges and learning difficulties.

Even with treatment, people with LGS or Dravet syndrome may continue to experience persistent seizures.

However, studies have shown that CBD, when taken with other anti-seizure medications, reduces the frequency and severity of seizures in people who have these disorders.2

A 2019 review of studies on Epidiolex showed a sustained seizure frequency reduction of between 30 and 63 percent.3 Additionally, seizures were about half as severe and the postictal (after seizure) state was less severe as well.

What About Other Seizure Types?

Studies using CBD for seizure control are focused on refractory seizures, which are seizures that are not easily controlled with anti-seizure treatments. It's still too soon to tell whether it will be beneficial and tolerable for people with other seizure types. As such, CBD is not approved for other types of seizures or epilepsy itself at this time.

Cannabidiol is a controversial treatment because it is one of the components of marijuana, a widely known recreational drug. There are strong opinions about the drug, and proponents advocate for its legalization for medical uses, while some advocate for the legalization of recreational use as well.

At this time, cannabidiol has been proven effective for only a few medical conditions. Due to the side effects, it is recommended to be used with caution.

If you have questions regarding whether cannabidiol is an appropriate treatment for you or someone you know, talk to your doctor first. You can use our Doctor Discussion Guide below to help start that conversation about treatment options and more.

Dosing

Epidiolex comes in an oral solution (liquid form), and the recommended dose is initiated based on weight.

It is generally started at a dose of 2.5 mg/kg twice per day and increased weekly. It can be increased up to a dose of 20 mg/kg per day if needed, but increased side effects have been found to occur at the higher dose.

Anti-seizure medications should be taken at the regularly scheduled times without skipping or combining doses.

Sometimes, children and adults who have LGS or Dravet syndrome have some difficulties taking oral medication due to difficulty swallowing, behavioral problems, and/or cognitive issues. It may be a challenge to get your child to take any medication, and you might need to develop strategies to help with this process.

Side Effects

The side effects of CBD that have been reported in the studies when it was added to other antiseizure medications included:

- Fever
- Upper respiratory tract infection/rhinitis
- Drowsiness
- Generalized fatigue
- Sleeping difficulties
- Weakness
- Decreased appetite
- Rashes
- Diarrhea
- Vomiting
- Status epilepticus (prolonged seizure requiring emergency attention)
- Fatigue
- Lethargy

In studies, these were more common in the first two weeks on Epidiolex, after which time they tended to diminish. Additionally, many of the studies on the drug involved at least one other anti-seizure drug as well, so the side effects may not all have been due to Epidiolex.

More severe side effects, which you should contact your doctor about right away, include

- Symptoms of liver injury: Jaundice (a yellowish color of the skin and eyes), abdominal pain, vomiting, and dark colored urine

- Mood changes: Depression, anxiety, and suicidal ideation

Myth Buster

CBD itself does not have abuse potential and does not produce the "high" that is typical of marijuana, so you do not need to worry about your child abusing the drug or becoming addicted to it. However, it is possible that others may misunderstand the effects of the drug, particularly because it is new and because it is derived from the same plant that marijuana is derived from.

Interactions

There's still much to be learned about how CBD interacts with other anti-seizure drugs.4

It's possible that CBD may raise the blood level of certain other anticonvulsants such as Topamax and Onfi (clobazam), and may result in side effects.

When used with other anti-seizure drugs, CBD can cause elevated liver enzymes, which is often a sign of liver injury.

In the aforementioned 2019 review of studies on this drug, however, researchers found that while adding Epidiolex to a treatment regimen may increase certain specific side effects, it may actually decrease the overall amount of side effects participants experienced.

Over-the-Counter CBD Products

A multitude of CBD-containing products are on the market, and some people have chosen to use them for seizure control. This trend is likely to grow, especially since the 2018 Farm Bill made hemp-derived products, including CBD, legal at the federal level.5

However, these products aren't regulated by the FDA and are largely untested. The FDA has warned that CBD products are often mislabeled or overpromise their supposed benefits.6Dosage and quality are likely to be far less consistent with other CBD products, which may put you at risk for more seizures. 

In fact, the FDA has issued warnings to many CBD businesses for illegal practices, including those related to the marketing of their products. In some cases, actual CBD content was negligible or less than 1 percent of what the label claimed.

A 2017 study published in JAMA found that 26 percent of products purchased online contained less CBD than their labels claimed.7

Warning

Some other CBD products contained other compounds from the marijuana plant, including tetrahydrocannabinol (THC)—the part that gets you "high."

A Word From Verywell

Given that CBD is a fairly new therapy for epilepsy, you may experience challenges when it comes to health insurance coverage or availability of the medication. If you do, be sure to involve your doctor, who can provide documentation that can help you get an approval for coverage and may be able to refer you to a source that will fill your prescription.