Prescription medication · Cannabinoid (Anticonvulsant)
cannabidiol
Also sold as Epidiolex. Epidiolex is used to treat seizures linked to Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), or tuberous sclerosis complex (TSC).
Data updated 2026-05-15
- 22,227
- FDA reportsModerately reported
- 8
- InteractionsFew interactions
- Rx
- Availability
What the data shows
cannabidiol (Epidiolex) is a prescription Cannabinoid (Anticonvulsant), reported at a middle-of-the-pack volume (22,227 FDA reports), with 8 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
cannabidiol (Epidiolex) is a prescription Cannabinoid (Anticonvulsant). Epidiolex is used to treat seizures linked to Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), or tuberous sclerosis complex (TSC).
Epidiolex is a medicine that contains cannabidiol. It is used to treat seizures in people with certain conditions.
Verify with FDA → · CMS NADAC pricing →
What it does
Epidiolex is used to treat seizures linked to Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), or tuberous sclerosis complex (TSC).
Common side effects
Feeling sleepy, Decreased appetite, Diarrhea
Key warnings
Epidiolex can cause liver problems.
The sections below are summarized in plain English from cannabidiol's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Epidiolex contains cannabidiol, which is a substance that may affect how the brain works. It is thought to reduce seizures by acting on certain brain chemicals. The exact way it works is not fully understood.
How to Take It
Take Epidiolex by mouth, using the provided syringe. For LGS or DS, the starting dose is 2.5 mg/kg twice a day. After one week, your doctor may increase the dose to 5 mg/kg twice a day. For TSC, the starting dose is 2.5 mg/kg twice a day, increasing weekly to 12.5 mg/kg twice a day. Follow your doctor's instructions carefully.
This is a plain-language summary of cannabidiol's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. Epidiolex may harm your unborn baby. There are pregnancy programs to monitor outcomes, so talk to your doctor about enrolling. It is not known if Epidiolex passes into breast milk, so talk to your doctor about the best way to feed your baby if you are taking this medicine.
This is a plain-language summary of cannabidiol's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take your next dose at the regular time.
This is a plain-language summary of cannabidiol's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store Epidiolex upright at room temperature (68°F to 77°F). Do not freeze. Keep the cap tightly closed and throw away any remaining medicine 12 weeks after opening the bottle.
Side Effects (from patient reports)
Based on 22,227 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for cannabidiol, by number of reports
- Seizure
Seizure
5,791 reports
- Hospital stay 2,073
Hospital stay
2,073 reports
- Diarrhea 1,695
Diarrhea
1,695 reports
- Sleepiness 1,242
Sleepiness
1,242 reports
- Death 1,204
Death
1,204 reports
- Tiredness 1,169
Tiredness
1,169 reports
- Weight loss 824
Weight loss
824 reports
- Weight gain 800
Weight gain
800 reports
- Vomiting 707
Vomiting
707 reports
- Decreased appetite 685
Decreased appetite
685 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for cannabidiol each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where cannabidiol sits
cannabidiol has more FDA adverse-event reports than 57% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is cannabidiol; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 22,227 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2010–2025.
Total Reports
22,227
Reports Mentioning Death
1,726
7.8% of reports — not proof of cause
Hospitalization Reports
6,502
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | SEIZURE | 5,791 |
| 3 | HOSPITALISATION | 2,073 |
| 5 | DIARRHOEA | 1,695 |
| 7 | SOMNOLENCE | 1,242 |
| 8 | DEATH | 1,204 |
| 9 | FATIGUE | 1,169 |
| 11 | WEIGHT DECREASED | 824 |
| 12 | WEIGHT INCREASED | 800 |
| 13 | VOMITING | 707 |
| 14 | DECREASED APPETITE | 685 |
| 15 | NAUSEA | 643 |
| 16 | CONDITION AGGRAVATED | 601 |
| 17 | PNEUMONIA | 593 |
| 18 | PRODUCT ADMINISTRATION INTERRUPTED | 524 |
| 19 | DRUG INTERACTION | 513 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Epidiolex can cause liver problems. Your doctor will check your liver before you start and during treatment. Tell your doctor right away if you feel very tired, have yellowing of the skin or eyes, dark urine, or loss of appetite. Epidiolex may also cause sleepiness or suicidal thoughts. Tell your doctor if you have any changes in mood or behavior.
Known Drug Interactions
7.2 Effect of EPIDIOLEX on Other Drugs Antiepileptic Drugs Clobazam Concomitant use of EPIDIOLEX with clobazam increases plasma concentrations of N‑desmethylclobazam, the active metabolite of clobazam [see Clinical Pharmacology ( 12.3 )], which may increase the risk of clobazam-related adverse reactions [see Adverse Reactions ( 6.1 ) and Warnings and Precautions ( 5.1 , 5.2 )]. Consider a reduction in dosage of clobazam if adverse reactions known to occur with clobazam are experienced when concomitantly used with EPIDIOLEX.
Mechanism: Cannabidiol increases the amount of an active byproduct of clobazam in your blood, which can lead to more side effects.
What to do: If you experience increased side effects, your doctor may need to reduce your dose of clobazam.
For CYP2C19 substrates (e.g., clopidogrel) where efficacy is mainly due to their active metabolite(s), concomitant use of EPIDIOLEX may decrease plasma concentration of the active metabolite(s) and may therefore decrease efficacy.
Mechanism: Cannabidiol interferes with how your body activates clopidogrel, which can make the medicine less effective at preventing blood clots.
What to do: Your doctor may need to adjust your treatment to make sure your medicine is still working correctly.
Increases in exposure of certain CYP1A2 substrates (e.g., theophylline, tizanidine) may be observed when concomitantly used with EPIDIOLEX.
Mechanism: Cannabidiol slows down the process your body uses to break down tizanidine, which can lead to higher levels of the drug in your blood.
What to do: Your doctor should monitor you for increased side effects and may need to lower your dose of tizanidine.
7.3 Concomitant Use of EPIDIOLEX and Valproate Concomitant use of EPIDIOLEX and valproate increases the incidence of liver enzyme elevations [see Warnings and Precautions ( 5.1 )]. If such elevations occur, consider discontinuation or reduction of EPIDIOLEX and/or concomitant valproate.
Mechanism: Taking these two medicines together can cause your liver enzymes to rise, which may indicate liver irritation.
What to do: Your doctor may need to lower your dose or stop one of the medicines if your liver tests show signs of stress.
( 7.2 ) 7.1 Effect of Other Drugs on EPIDIOLEX Strong CYP3A4 or CYP2C19 Inducers Concomitant use with a strong CYP3A4 and CYP2C19 inducer (rifampin 600 mg once daily) decreased cannabidiol and 7‑OH‑CBD plasma concentrations by approximately 32% and 63%.
Mechanism: Rifampin makes your body clear cannabidiol much faster than usual, which makes the medicine less effective.
What to do: Your doctor may need to adjust your dose of cannabidiol to ensure it still works properly while you are taking rifampin.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
What should I do if I experience side effects?
Can I drive while taking Epidiolex?
Will Epidiolex cure my seizures?
How long will I need to take Epidiolex?
Can I take other medicines with Epidiolex?
What if I accidentally take too much Epidiolex?
How will I know if Epidiolex is working?
Does Epidiolex contain THC?
Can children take Epidiolex?
How should I measure the dose?
What are the common side effects of cannabidiol?
Does cannabidiol interact with other medications?
What drug class is cannabidiol?
Is cannabidiol safe during pregnancy?
Related Medications in Cannabinoid (Anticonvulsant)
Other drugs grouped near cannabidiol - same-class peers and common alternatives.
brivaracetam
Briviact
Brivaracetam is a medicine used to treat partial-onset seizures.
Compare with cannabidiol →
carbamazepine
Tegretol
Carbamazepine is a medicine used to control seizures and treat nerve pain.
Compare with cannabidiol →
cenobamate
Xcopri
Xcopri is a medicine used to treat partial-onset seizures in adults.
Compare with cannabidiol →
clobazam
Onfi, Sympazan
Clobazam oral suspension is a medicine used with other medicines to treat seizures caused by Lennox-Gastaut syndrome.
Compare with cannabidiol →
clonazepam
Klonopin
Clonazepam is a medicine that belongs to the benzodiazepine class.
Compare with cannabidiol →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
Save on cannabidiol
Compare prices and find discounts at pharmacies near you. Free coupons can save up to 80% on prescriptions.
Disclosure: This link may earn us a commission at no extra cost to you. See our terms.
What the FDA Data Shows for cannabidiol
The FDA label for cannabidiol (sold under brand names such as Epidiolex) classifies it as a prescription-only medication in the Cannabinoid (Anticonvulsant) class. Epidiolex is used to treat seizures linked to Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), or tuberous sclerosis complex (TSC). Official labeling lists 10 commonly reported side effects, including Feeling sleepy, Decreased appetite, Diarrhea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 22,227 voluntary reports. The database also lists 8 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. Acquisition-cost data is surveyed weekly by CMS and updated as manufacturers report changes.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: July 31, 2025
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages