Drug · FAERS side-effect profile with label screen
Cannabidiol side effects: what 23,264 FDA adverse event reports show
Drug class
Cytochrome P450 2C8 Inhibitors, Cytochrome P450 2C9 Inhibitors
FDA label (mechanism-of-action class)
Brand names
Epidiolex
openFDA label
Who reports
23,264 reports · 59% serious · 1,868 with death outcome · 49% female
openFDA FAERS counts, all years, deduplication not applied
Used for
EPIDIOLEX is indicated for the treatment of seizures associated with Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), or tuberous sclerosis complex (TSC) in patients 1 year of age and older. EPIDIOLEX is indicated for the treatment of seizures associated with Lennox-Gastaut syndrome, Dravet syndrome, or tuberous sclerosis complex in patients 1 year of age and older ( 1 )
FDA label, Indications and Usage
What it is
Cannabidiol is a cannabinoid designated chemically as 2-[(1R,6R)-3-Methyl-6-(1-methylethenyl)-2-cyclohexen-1-yl]-5-pentyl-1,3-benzenediol (IUPAC/CAS).
FDA label, Description section
Boxed warning
None in the current label
How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation.
Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)?
That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.
Causality screen of the 40 strongest signals
Labeled (related wording) 5Likely indication confounding 7Reporting / coding artifact 5Lab value / disease marker 3Not in label — unassessed 20
What the badges mean
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 1,015 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Malignant cranial nerve neoplasm | 18 | 1,999.0 869.3–4,596.9ROR 2,000.5 · χ² 10,453 / p <1e-300 | 371.8 EB05 248.8 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=18 | not reported in cached trials |
| Retro-orbital neoplasm | 18 | 456.9 258.8–806.6ROR 457.3 · χ² 5,110 / p <1e-300 | 228.9 EB05 153.2 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=18 | not reported in cached trials |
| Seizure cluster | 168 | 238.4 201.2–282.6ROR 240.2 · χ² 31,131 / p <1e-300 | 184.3 EB05 162.0 · IC025 +6.7 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=141 | NCT02224573: 2/315 (0.6%) on Cannabidiol (serious AE) |
| Electroencephalogram | 11 | 217.2 112.3–419.8ROR 217.3 · χ² 1,732 / p <1e-300 | 134.5 EB05 80.2 · IC025 +3.3 3/3 methods agree | Lab value / disease marker | serious n=11 | not reported in cached trials |
| Atonic seizures | 142 | 195.6 163.2–234.5ROR 196.8 · χ² 22,372 / p <1e-300 | 157.1 EB05 136.6 · IC025 +6.4 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=104 | not reported in cached trials |
| Vagal nerve stimulator implantation | 50 | 182.8 134.9–247.8ROR 183.2 · χ² 7,348 / p <1e-300 | 143.6 EB05 113.2 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious n=47 | not reported in cached trials |
| Change in seizure presentation | 95 | 152.6 122.8–189.7ROR 153.2 · χ² 12,083 / p <1e-300 | 127.1 EB05 107.1 · IC025 +5.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=73 | not reported in cached trials |
| Lennox-gastaut syndrome | 24 | 107.7 70.5–164.5ROR 107.8 · χ² 2,168 / p <1e-300 | 89.5 EB05 63.3 · IC025 +4.3 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=24 · ♀ 18% (drug 49%) | not reported in cached trials |
| Emergency care | 308 | 104.2 92.7–117.2ROR 105.6 · χ² 28,088 / p <1e-300 | 92.8 EB05 84.5 · IC025 +6.2 3/3 methods agree | Not in label — unassessed | serious n=230 · 86% consumer | not reported in cached trials |
| Medical device battery replacement | 12 | 92.7 51.2–168.0ROR 92.8 · χ² 904 / p 6e-199 | 74.5 EB05 45.4 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=11 | not reported in cached trials |
| Aortic valve thickening | 14 | 88.2 50.9–152.8ROR 88.3 · χ² 1,020 / p 4e-224 | 72.7 EB05 46.0 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=14 | not reported in cached trials |
| Neuroblastoma recurrent | 17 | 83.0 50.5–136.4ROR 83.0 · χ² 1,185 / p 5e-260 | 70.2 EB05 46.4 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious n=17 | not reported in cached trials |
| Sudden unexplained death in epilepsy | 40 | 71.9 52.1–99.3ROR 72.1 · χ² 2,523 / p <1e-300 | 64.7 EB05 49.5 · IC025 +4.7 3/3 methods agree | Labeled (related wording) related wording | serious n=40 | NCT02224573: 4/315 (1.3%) on Cannabidiol (serious AE) |
| Product administration interrupted | 563 | 71.4 65.6–77.7ROR 73.1 · χ² 36,113 / p <1e-300 | 66.0 EB05 61.6 · IC025 +5.8 3/3 methods agree | Reporting / coding artifact | serious n=390 | not reported in cached trials |
| Greater trochanteric pain syndrome | 13 | 66.0 37.6–115.9ROR 66.0 · χ² 715 / p 7e-158 | 56.7 EB05 35.2 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious n=13 | not reported in cached trials |
| Epileptic encephalopathy | 14 | 61.0 35.5–104.8ROR 61.0 · χ² 718 / p 2e-158 | 53.2 EB05 33.7 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=14 | not reported in cached trials |
| Mitral valve thickening | 17 | 58.8 36.0–96.0ROR 58.8 · χ² 852 / p 1e-187 | 52.1 EB05 34.5 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=17 | not reported in cached trials |
| Tonic convulsion | 82 | 56.0 44.8–69.9ROR 56.1 · χ² 4,112 / p <1e-300 | 52.1 EB05 43.3 · IC025 +5.0 3/3 methods agree | Not in label — unassessed | serious n=74 | not reported in cached trials |
| Weight abnormal | 130 | 51.7 43.3–61.7ROR 52.0 · χ² 6,061 / p <1e-300 | 48.6 EB05 42.0 · IC025 +5.1 3/3 methods agree | Labeled (related wording) related wording | serious n=10 | NCT02224573: 1/315 (0.3%) on Cannabidiol (serious AE) |
| Seizure | 6,024 | 49.9 48.8–51.0ROR 67.0 · χ² 274,832 / p <1e-300 | 47.3 EB05 46.3 · IC025 +5.5 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 33.5 | NCT02224573: 4/315 (1.3%) on Cannabidiol (serious AE) |
| Post viral fatigue syndrome | 12 | 46.4 25.9–82.8ROR 46.4 · χ² 464 / p 3e-103 | 41.4 EB05 25.2 · IC025 +3.0 3/3 methods agree | Labeled (related wording) related wording | serious n=12 | not reported in cached trials |
| Myoclonic epilepsy | 68 | 43.6 34.2–55.6ROR 43.7 · χ² 2,657 / p <1e-300 | 41.2 EB05 33.6 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious n=62 | NCT02224573: 1/366 (0.3%) on Cannabidiol (serious AE) |
| Anticonvulsant drug level increased | 75 | 43.5 34.5–54.9ROR 43.7 · χ² 2,930 / p <1e-300 | 41.1 EB05 33.9 · IC025 +4.7 3/3 methods agree | Lab value / disease marker | serious n=26 | NCT02224573: 2/315 (0.6%) on Cannabidiol (serious AE) |
| Multiple-drug resistance | 138 | 42.0 35.5–49.8ROR 42.3 · χ² 5,241 / p <1e-300 | 40.0 EB05 34.7 · IC025 +4.9 3/3 methods agree | Reporting / coding artifact | serious n=106 · 91% clinician | not reported in cached trials |
| Product supply issue | 303 | 40.4 36.0–45.3ROR 40.9 · χ² 11,106 / p <1e-300 | 38.6 EB05 35.1 · IC025 +5.0 3/3 methods agree | Reporting / coding artifact | serious n=144 · 78% consumer | not reported in cached trials |
| Feeding intolerance | 15 | 31.4 18.8–52.6ROR 31.5 · χ² 398 / p 8e-89 | 29.4 EB05 18.9 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=15 | NCT02224573: 1/366 (0.3%) on Cannabidiol (serious AE) |
| Device related thrombosis | 30 | 28.4 19.8–40.9ROR 28.5 · χ² 743 / p 8e-164 | 27.1 EB05 19.9 · IC025 +3.7 3/3 methods agree | Reporting / coding artifact | serious n=30 · ♀ 100% (drug 49%) · 100% clinician | not reported in cached trials |
| Therapeutic product effective for unapproved indication | 10 | 25.4 13.5–47.6ROR 25.4 · χ² 205 / p 1e-46 | 23.5 EB05 13.2 · IC025 +2.5 3/3 methods agree | Labeled (related wording) related wording | serious n=9 | not reported in cached trials |
| Petit mal epilepsy | 136 | 24.7 20.9–29.3ROR 24.9 · χ² 2,992 / p <1e-300 | 24.0 EB05 20.8 · IC025 +4.2 3/3 methods agree | Labeled (related wording) related wording | serious n=121 | not reported in cached trials |
| Behaviour disorder | 141 | 24.6 20.8–29.0ROR 24.7 · χ² 3,082 / p <1e-300 | 23.9 EB05 20.8 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=108 | NCT02224573: 2/315 (0.6%) on Cannabidiol (serious AE) |
| Therapy responder | 13 | 24.4 14.0–42.3ROR 24.4 · χ² 261 / p 5e-59 | 22.9 EB05 14.0 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | – | not reported in cached trials |
| Metal poisoning | 15 | 23.8 14.3–39.7ROR 23.8 · χ² 297 / p 7e-67 | 22.5 EB05 14.3 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=15 | not reported in cached trials |
| Poverty of speech | 10 | 23.5 12.5–44.0ROR 23.5 · χ² 189 / p 3e-43 | 21.7 EB05 12.1 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | – | not reported in cached trials |
| Ammonia abnormal | 10 | 22.8 12.2–42.8ROR 22.8 · χ² 183 / p 6e-42 | 21.1 EB05 11.6 · IC025 +2.4 3/3 methods agree | Lab value / disease marker | serious n=9 | NCT02224573: 1/315 (0.3%) on Cannabidiol (serious AE) |
| Brain operation | 55 | 22.5 17.2–29.4ROR 22.6 · χ² 1,082 / p 2e-237 | 21.8 EB05 17.4 · IC025 +3.8 3/3 methods agree | Reporting / coding artifact | serious n=54 · 75% consumer | not reported in cached trials |
| Infantile spasms | 17 | 21.9 13.6–35.5ROR 21.9 · χ² 311 / p 6e-70 | 20.9 EB05 13.7 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=17 | not reported in cached trials |
| Partial seizures with secondary generalisation | 11 | 21.6 11.9–39.3ROR 21.6 · χ² 192 / p 7e-44 | 20.1 EB05 11.4 · IC025 +2.5 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=11 | not reported in cached trials |
| Generalised tonic-clonic seizure | 381 | 21.5 19.4–23.7ROR 21.8 · χ² 7,245 / p <1e-300 | 21.0 EB05 19.3 · IC025 +4.2 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 16.7 | NCT02224573: 4/315 (1.3%) on Cannabidiol (serious AE) |
| Drug withdrawal convulsions | 38 | 19.6 14.2–27.0ROR 19.6 · χ² 638 / p 6e-141 | 19.0 EB05 14.4 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=36 · 76% consumer | not reported in cached trials |
| Head banging | 12 | 19.2 10.8–34.0ROR 19.2 · χ² 185 / p 2e-42 | 17.9 EB05 10.2 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | – | not reported in cached trials |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Cannabidiol as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (10 of 40 signal terms matched).
- NCT02224573 — An Open Label Extension Study of Cannabidiol (GWP42003-P) in Children and Adults With Dravet or Lennox-Gastaut (N=681, PHASE3; 301 AE terms posted; arms: Dravet Syndrome; Lennox-Gastaut Syndrome)
Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Seizure | 6,024 | 49.9 48.8–51.0ROR 67.0 · χ² 274,832 / p <1e-300 | 47.3 EB05 46.3 · IC025 +5.5 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 33.5 | NCT02224573: 4/315 (1.3%) on Cannabidiol (serious AE) |
| Hospitalisation | 2,450 | 14.7 14.2–15.3ROR 16.3 · χ² 31,021 / p <1e-300 | 14.5 EB05 14.0 · IC025 +3.8 3/3 methods agree | Reporting / coding artifact | serious PRR 14.4 · 82% consumer | not reported in cached trials |
| Off label use (used outside approved label) | 2,401 | 2.5 2.4–2.6ROR 2.7 · χ² 2,242 / p <1e-300 | 2.5 EB05 2.4 · IC025 +1.3 3/3 methods agree | Reporting / coding artifact | serious PRR 3.6 | not reported in cached trials |
| Product use in unapproved indication | 1,802 | 6.7 6.4–7.0ROR 7.2 · χ² 8,754 / p <1e-300 | 6.6 EB05 6.4 · IC025 +2.7 3/3 methods agree | Reporting / coding artifact | serious PRR 4.8 | not reported in cached trials |
| Diarrhoea (diarrhea) | 1,731 | 2.4 2.3–2.5ROR 2.5 · χ² 1,497 / p <1e-300 | 2.4 EB05 2.3 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 1.6 | NCT02224573: 5/315 (1.6%) on Cannabidiol (serious AE) |
| Drug ineffective (drug did not work) | 1,391 | 1.0 0.9–1.0ROR 0.9 · χ² 4 / p 0.030 | 1.0 EB05 0.9 · IC025 -0.2 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 1.8 | not reported in cached trials |
| Death | 1,325 | 1.4 1.3–1.5ROR 1.4 · χ² 149 / p 2e-34 | 1.4 EB05 1.3 · IC025 +0.4 | Outcome field, not a reaction | serious PRR 1.3 | NCT02224573: 4/315 (1.3%) on Cannabidiol (serious AE) |
| Somnolence (drowsiness) | 1,292 | 5.8 5.5–6.1ROR 6.1 · χ² 5,173 / p <1e-300 | 5.8 EB05 5.5 · IC025 +2.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.1 | NCT02224573: 2/315 (0.6%) on Cannabidiol (serious AE) |
| Fatigue (tiredness) | 1,203 | 1.4 1.3–1.5ROR 1.4 · χ² 140 / p 1e-32 | 1.4 EB05 1.3 · IC025 +0.4 | Labeled adverse reaction exact term | serious PRR 1.3 | NCT02224573: 1/315 (0.3%) on Cannabidiol (serious AE) |
| Product dose omission issue | 1,161 | 3.7 3.5–3.9ROR 3.8 · χ² 2,292 / p <1e-300 | 3.7 EB05 3.5 · IC025 +1.8 3/3 methods agree | Reporting / coding artifact | serious PRR 8.1 | not reported in cached trials |
| Weight decreased (weight loss) | 864 | 2.8 2.6–3.0ROR 2.9 · χ² 1,006 / p 5e-221 | 2.8 EB05 2.6 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.1 | NCT02224573: 1/315 (0.3%) on Cannabidiol (serious AE) |
| Weight increased (weight gain) | 827 | 3.4 3.1–3.6ROR 3.4 · χ² 1,374 / p <1e-300 | 3.3 EB05 3.2 · IC025 +1.6 3/3 methods agree | Labeled (related wording) related wording | serious PRR 1.8 | NCT02224573: 1/315 (0.3%) on Cannabidiol (serious AE) |
| Vomiting | 735 | 1.4 1.3–1.5ROR 1.4 · χ² 90 / p 1e-21 | 1.4 EB05 1.3 · IC025 +0.4 | Labeled adverse reaction exact term | serious PRR 1.3 | NCT02224573: 13/366 (3.6%) on Cannabidiol (serious AE) |
| Decreased appetite (loss of appetite) | 714 | 2.8 2.6–3.0ROR 2.8 · χ² 821 / p 7e-181 | 2.8 EB05 2.6 · IC025 +1.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 1.9 | NCT02224573: 3/366 (0.8%) on Cannabidiol (serious AE) |
| Nausea | 661 | 0.8 0.7–0.8ROR 0.7 · χ² 54 / p 8e-14 | 0.8 EB05 0.7 · IC025 -0.5 PRR-only: not supported by EBGM or IC | Labeled adverse reaction exact term | serious PRR 0.9 · ♀ 70% (drug 49%) | NCT02224573: 3/366 (0.8%) on Cannabidiol (serious AE) |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- Vagal nerve stimulator implantation — n=50, PRR 182.8
- Emergency care — n=308, PRR 104.2
- Tonic convulsion — n=82, PRR 56.0
- Myoclonic epilepsy — n=68, PRR 43.6 (also seen in trial arm)
- Behaviour disorder — n=141, PRR 24.6 (also seen in trial arm)
- Drug withdrawal convulsions — n=38, PRR 19.6
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Cannabidiol?
In FDA FAERS, the most frequently co-reported reaction terms for Cannabidiol are seizure, diarrhoea, somnolence, fatigue, weight decreased, weight increased. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Cannabidiol have an FDA boxed warning?
No. The FDA label retrieved for Cannabidiol has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Cannabidiol causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 8bf27097-4870-43fb-94f0-f3d0871d1eec, effective 20260529; matched on
openfda.generic_name.exact:"CANNABIDIOL") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 1,055 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath - ClinicalTrials.gov API v2 (query
CANNABIDIOL, results-bearing studies sorted by enrollment)
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.