Epidiolex (Cannabidiol) - Oral

What Is Epidiolex?

Epidiolex (cannabidiol) is a prescription medicine that prevents seizures from neurological syndromes. It's available as a solution taken by mouth (oral), usually twice daily. While Epidiolex (cannabidiol) was a controlled substance (Schedule V), it is now no longer a scheduled substance as of 2020.

The marijuana (Cannabis sativa) plant contains both cannabidiol and tetrahydrocannabinol (THC) and other components. Cannabidiol interacts with cannabinoid receptors in the brain. THC is the main psychoactive chemical in marijuana. While cannabidiol and THC are both used medically and recreationally, this article focuses on the medical use of the prescription product Epidiolex (cannabidiol).

The way that Epidiolex prevents seizures is not known. According to the manufacturer, the anti-seizure effect is unrelated to its interaction with cannabinoid receptors in the brain. Research suggests that cannabidiol decreases overactive nerves in different ways.

Drug Facts

Generic Name: Cannabidiol

Brand Name(s): Epidiolex

Drug Availability: Prescription

Therapeutic Classification: Anticonvulsant

Available Generically: No

Controlled Substance: No

Administration Route: Oral

Active Ingredient: Cannabidiol

Dosage Form(s): Solution

What Is Epidiolex Used For?

This medicine is approved for adults and children 1-year-old and older. It’s used for preventing seizures that occur due to:

These conditions often cause refractory epilepsy with seizures that aren’t easily prevented with other anticonvulsants (anti-seizure drugs [AEDs]). Often, Epidiolex is taken with other AEDs to prevent seizures.

How to Take Epidiolex

Epidiolex comes in a bottle with a measuring device and a syringe. You should use the measuring device to measure the oral solution. Use the syringe to take or give the medicine to your child by mouth. If your child is very young or unable to take care of themselves, they may need assistance taking this medicine.

Food can affect the concentration of the medicine in your body. It can be taken with or without food, but it’s essential always to take it in the same way (for example, either always before meals or always after meals), so the drug concentration will stay the same.


Epidiolex comes in a bottle. It should be stored upright. Keep your medications tightly closed and out of the reach of children and pets, ideally locked in a cabinet or closet. Do not store your medicines in the bathroom.

It should be kept at a standard room temperature of 20 to 25 degrees Celsius (C), 68 to 77 degrees Fahrenheit (F), with excursions permitted between 15 to 30 degrees C (59 to 86 degrees F). Do not freeze.

You should use it within 12 weeks of opening the bottle. Avoid using any of the solution past 12 weeks after opening. Ask your pharmacist how to discard any remaining solution and if there are any medicine take-back programs in your area.

Avoid pouring unused and expired drugs down the drain or in the toilet. Ask your pharmacist or healthcare provider about the best ways to dispose of this medicine. Visit the Food and Drug Administration's (FDA) website to know where and how to discard all unused and expired drugs. You can also find disposal boxes in your area. Ask your pharmacist or healthcare provider if you have any questions about the best ways to dispose of your medications.

If you travel with Epidiolex, get familiar with your final destination's regulations. In general, be sure to make a copy of your Epidiolex prescription. Keep your medication in its original container from your pharmacy with your name on the label. Ask your pharmacist or healthcare provider if you have any questions about traveling with your medicine.

Off-Label Uses

Cannabidiol has been used off-label to treat several conditions. These uses are mostly considered “investigational” (i.e., not well-established).

A few of the off-label uses are:

  • Anxiety disorders
  • Behavioral or developmental disorders in children and adolescents
  • Protection from nerve damage in neurological (brain) diseases, including Parkinson’s disease 

The dosing and side effects may be different when it’s used for treating these conditions than when it’s used for treating epilepsy.

How Long Does Epidiolex Take to Work?

The time it takes Epidiolex to work may be different for everyone. Be sure to check with your healthcare provider or pharmacist if you've any questions.

What Are the Side Effects of Epidiolex?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

The most common side effects for people who have Lennox-Gastaut Syndrome and Dravet Syndrome:

  • Tiredness, lack of energy
  • Decreased appetite
  • Diarrhea
  • Feeling sick
  • Rash
  • Trouble sleeping
  • Infections

The most common side effects for people who have tuberous sclerosis:

Be sure to tell your healthcare provider if you or your child have been experiencing these side effects. If the medicine causes them, they can often be treated, or your treatment may need to be changed. However, these symptoms may also be due to other causes which should be diagnosed and treated. Be sure to reach out to your healthcare provider.

Severe Side Effects

This medicine may cause harmful side effects. Your healthcare provider may monitor for serious side effects.

Severe side effects:

  • Liver damage may cause jaundice (yellow discoloration of the skin and eyes) or enlargement of your stomach area (abdomen). 
  • Severe tiredness: It can be dangerous to operate machinery using Epidiolex, leading to injuries, such as falls.
  • Suicidal ideation or actions: Thinking, planning, or taking action to commit suicide may occur while taking this medicine.
  • Hypersensitivity reaction: Epidiolex may cause a rash, swelling of the face or body, difficulty breathing, and/or passing out.

Get medical attention immediately if you have any of the severe side effects of Epidiolex.

Long-Term Side Effects

This medicine may cause lasting problems even after it is discontinued. These include:

  • Neurological or behavior changes.

Report Side Effects

Epidiolex may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Epidiolex Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (oral liquid):
    • For seizures in patients with Lennox-Gastaut Syndrome or Dravet Syndrome:
      • Adults and children 1 year of age and older—Dose is based on body weight and must be determined by your doctor. The dose is 2.5 milligram per kilogram (mg/kg) 2 times a day. Your doctor may adjust your dose as needed and tolerated. However, the dose is usually not more than 10 mg/kg 2 times a day.
      • Children younger than 1 year of age—Use and dose must be determined by your doctor.
    • For seizures in patients with tuberous sclerosis complex:
      • Adults and children 1 year of age and older—Dose is based on body weight and must be determined by your doctor. The dose is 2.5 milligram per kilogram (mg/kg) 2 times a day. Your doctor may adjust your dose as needed and tolerated. However, the dose is usually not more than 12.5 mg/kg 2 times a day.
      • Children younger than 1 year of age—Use and dose must be determined by your doctor.


The following modifications (changes) should be kept in mind when using Epidiolex:

Severe allergic reaction: Avoid using Epidiolex if you have a known allergy to it or its ingredients. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.

Pregnancy: We don't know enough about the safety and effectiveness of Epidiolex in pregnant people and their unborn fetuses. Discuss with your healthcare provider if you plan to become pregnant or are pregnant, and weigh the benefits and risks of taking Epidiolex during your pregnancy.

Breastfeeding: There's not enough data about how much Epidiolex can be found in breast milk. We don't know enough about the safety of Epidiolex in human breast milk and nursing babies. Talk with your healthcare provider if you plan to breastfeed, to weigh the benefits and risks of taking Epidiolex while nursing and the different ways to feed your baby.

Adults over 65: Some older adults may be more sensitive to Epidiolex's side effects. The general guidance is to start at a lower dose and modify as needed.

Children: For children, the dose is typically weight-based and taken by mouth twice a day.

Liver problems: For people with liver disease, the dose should be increased slowly to a target dose lower than the standard dose.

Missed Dose

If you accidentally forgot your Epidiolex dose, take it as soon as you remember. If it's already close to your next scheduled dose, skip the missed dose and take the following dose at your next scheduled dosing time. Don't try to double up to make up for the missed dose.

Try to find ways that work for you to help yourself remember to keep your appointments and take your medication routinely. If you miss too many doses, Epidiolex might be less effective at treating your condition.

Overdose: What Happens If I Take Too Much Epidiolex?

Taking too much Epidiolex can cause serious effects, including vomiting, sleepiness (somnolence), and loss of consciousness. If you have taken too much, seek medical attention. You will likely need close medical observation, and you may need to be treated for symptoms of an overdose.

What Happens If I Overdose on Epidiolex?

If you think you or someone else may have overdosed on Epidiolex, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Epidiolex, call 911 immediately.


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It is very important that your doctor check your or your child's progress at regular visits to make sure this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Do not suddenly stop using this medicine without first checking with your doctor. Your doctor will need to slowly decrease your dose before you stop it completely. Stopping the medicine suddenly may cause your seizures to return or to occur more often.

Check with your doctor right away if you or your child have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.

This medicine may make you or your child drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Check with your doctor before using this medicine with alcohol or other medicines that affect the central nervous system (CNS). The use of alcohol or other medicines that affect the CNS with cannabidiol may worsen the side effects of this medicine, such as dizziness, poor concentration, drowsiness, unusual dreams, and trouble with sleeping. Some examples of medicines that affect the CNS are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicines, medicine for depression, medicine for anxiety, prescription pain medicine or narcotics, medicine for attention deficit and hyperactivity disorder, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics.

Cannabidiol may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. Also tell your doctor if you or your child have sudden or strong feelings, such as feeling nervous, angry, restless, violent, or scared. If you or your caregiver notice any of these side effects, tell your doctor right away.

This medicine may cause serious allergic reactions, including angioedema. These can be life-threatening and require immediate medical attention. Tell your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals after using this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Epidiolex?

You should not take Epidiolex if you have ever been allergic to this medicine. You may be prescribed this medicine with caution if you have liver failure, are pregnant, or are breastfeeding.

What Other Medications Interact With Epidiolex?

Epidiolex can interact with several medications, sometimes causing changes in the concentration of one or both drugs and increasing the risk of specific side effects.

  • Rifampin lowers the concentration of Epidiolex.
  • Using Epidiolex with clobazam, diazepam, or phenytoin may increase the risk of adverse reactions.
  • Using Epidiolex with valproate increases the possibility of high liver enzymes (markers of possible liver damage).
  • Using Epidiolex with alcohol or any other sedatives increases the risk of sedation.

What Medications Are Similar?

There are several medical and therapeutic forms of cannabidiol. Epidiolex is the only cannabidiol medication that is approved for treating epilepsy. Do not take other forms of cannabidiol while taking Epidiolex, and do not take any other forms of cannabidiol for treating seizures—they are not formulated for seizure treatment.

Frequently Asked Questions

  • What is Epidiolex used for?

    This medication prevents seizures in people with Dravet syndrome, Lennox Gastaut syndrome, and tuberous sclerosis.

  • How does Epidiolex work?

    Epidiolex may stop overactive nerves by changing how synapses respond in the brain, making channels in the brain less sensitive and preventing adenosine uptake.

  • What medicines should not be taken with Epidiolex?

    This medicine can interact with sedatives, causing a severe sedative effect. It can also increase the risk of liver damage when taken with valproate. And it can increase the risk of adverse reactions when taken with phenytoin, diazepam, or clobazam.

  • How long does it take for Epidiolex to work?

    This medicine can begin to take effect within a few days. It is expected to take about a week for the level to stabilize in the body and exert anti-seizure effects.

  • What are the side effects of Epidiolex?

    The most common side effects include tiredness, loss of appetite, and diarrhea. Serious side effects include a severe allergic reaction, liver damage, suicidal thoughts or actions, and extreme fatigue.

How Can I Stay Healthy While Taking Epidiolex?

There are several strategies for staying healthy while taking Epidiolex.

  • Sometimes, people prescribed this medicine also have underlying problems or may not understand the need for treatment. Have a plan for communicating and navigating challenges in administering the medication if you need to. Speak with your healthcare provider.
  • It is essential to avoid driving, using machinery, climbing ladders, or other activities that require concentration or balance until you know whether this medicine makes you sleepy.
  • Avoid seizure triggers, such as alcohol, drugs, skipping medicine, skipping meals, lack of sleep, and bright lights.
  • Have an emergency plan in place in case a seizure occurs.
  • Be aware of this drug's mild and severe side effects, and get prompt medical attention if you experience any dangerous side effects.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  5. Efron D. Potential therapeutic uses of cannabinoids to treat behavioural problems in children and adolescents with developmental disorders. Aust J Gen Pract. 2021;50(6):352-355. doi:10.31128/AJGP-01-21-5809

  6. Ferreira-Junior NC, Campos AC, Guimarães FS, et al. Biological bases for a possible effect of cannabidiol in Parkinson's disease. Braz J Psychiatry. 2020;42(2):218-224. doi:10.1590/1516-4446-2019-0460

  7. Huestis MA, Solimini R, Pichini S, Pacifici R, Carlier J, Busardò FP. Cannabidiol adverse effects and toxicity. Curr Neuropharmacol. 2019;17(10):974-989. doi:10.2174/1570159X17666190603171901

By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.