Modafinil side effects: what 32,095 FDA adverse event reports show
Drug class
Sympathomimetic-like Agent
Who reports
32,095 reports · 58% serious · 1,070 with death outcome · 70% female
Used for
Modafinil tablets are indicated to improve wakefulness in adult patients with excessive sleepiness associated with narcolepsy, obstructive sleep apnea (OSA), or shift work disorder (SWD). Limitations of Use In OSA, modafinil tablets are indicated to treat excessive sleepiness and not as treatment for the underlying obstruction.
What it is
Modafinil, USP is a wakefulness-promoting agent for oral administration. Modafinil, USP is a racemic compound.
Boxed warning
None in the current label
Causality screen of the 40 strongest signals
What the badges mean
- Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
- 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, for the 300 most-reported drugs, adjusted for age band), and flags pairs whose reports are unusually skewed by sex or come mostly from consumers. Each row also shows the PRR against the other drugs of the same FDA class, which removes most confounding by the condition being treated, and a calibrated p-value: on validation, known non-causes average an ROR of about 2, so significance is judged against that empirical null (✓ = p < 0.05 after calibration). 1,155 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Cataplexy | 280 | 159.5 140.0–181.7ROR 160.9 · calibrated p 3e-9 ✓ | 126.9 EB05 114.9 · IC025 +6.5 3/3 methods agree | Not in label — unassessed | serious n=243 | not reported in cached trials |
| Pre-existing condition improved | 556 | 63.1 57.9–68.8ROR 64.2 · calibrated p 3e-6 ✓ | 57.4 EB05 53.5 · IC025 +5.6 3/3 methods agree | Not in label — unassessed | serious n=301 | not reported in cached trials |
| Periodic limb movement disorder | 32 | 62.0 43.2–89.2ROR 62.1 · calibrated p 7e-6 ✓ | 54.9 EB05 40.7 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=24 | not reported in cached trials |
| Narcolepsy | 154 | 58.0 49.2–68.4ROR 58.3 · calibrated p 6e-6 ✓ | 53.0 EB05 46.3 · IC025 +5.2 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=141 | not reported in cached trials |
| Parasomnia | 53 | 53.4 40.3–70.6ROR 53.5 · calibrated p 1e-5 ✓ | 48.6 EB05 38.5 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious n=35 | not reported in cached trials |
| Sleep-related eating disorder | 65 | 48.5 37.7–62.4ROR 48.6 · calibrated p 2e-5 ✓ | 44.7 EB05 36.3 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=40 | not reported in cached trials |
| Product administration interrupted | 454 | 41.1 37.4–45.1ROR 41.6 · calibrated p 4e-5 ✓ | 38.6 EB05 35.7 · IC025 +5.1 3/3 methods agree | Reporting / coding artifact | serious n=427 | not reported in cached trials |
| Sleep attacks | 28 | 41.0 28.0–60.0ROR 41.0 · calibrated p 8e-5 ✓ | 37.7 EB05 27.3 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious n=16 | not reported in cached trials |
| Sleep paralysis | 79 | 37.2 29.7–46.7ROR 37.3 · calibrated p 9e-5 ✓ | 35.0 EB05 29.0 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=51 | not reported in cached trials |
| Abnormal sleep-related event | 64 | 33.1 25.8–42.6ROR 33.2 · calibrated p 2e-4 ✓ | 31.3 EB05 25.4 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=31 | not reported in cached trials |
| Obstructive sleep apnoea syndrome | 66 | 32.4 25.3–41.5ROR 32.4 · calibrated p 2e-4 ✓ | 30.6 EB05 24.9 · IC025 +4.2 3/3 methods agree | Likely indication confounding term in indications | serious n=61 | not reported in cached trials |
| Snoring | 164 | 29.7 25.4–34.7ROR 29.8 · calibrated p 3e-4 ✓ | 28.3 EB05 24.9 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=99 | not reported in cached trials |
| Sleep apnoea syndrome | 775 | 27.6 25.7–29.6ROR 28.2 · calibrated p 4e-4 ✓ | 26.5 EB05 24.9 · IC025 +4.6 3/3 methods agree | Likely indication confounding term in indications | serious PRR 29.1 | not reported in cached trials |
| Enuresis | 161 | 27.1 23.1–31.7ROR 27.2 · calibrated p 5e-4 ✓ | 26.0 EB05 22.8 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious n=96 | not reported in cached trials |
| Blood pressure measurement | 21 | 22.1 14.3–34.2ROR 22.1 · calibrated p 0.002 ✓ | 21.0 EB05 14.4 · IC025 +3.1 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=21 | not reported in cached trials |
| Somnambulism | 216 | 22.1 19.3–25.3ROR 22.3 · calibrated p 0.001 ✓ | 21.4 EB05 19.1 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=144 | not reported in cached trials |
| Postural orthostatic tachycardia syndrome | 42 | 21.6 15.9–29.4ROR 21.6 · calibrated p 0.002 ✓ | 20.7 EB05 16.0 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=32 | not reported in cached trials |
| Secondary progressive multiple sclerosis | 48 | 16.9 12.7–22.6ROR 17.0 · calibrated p 0.005 ✓ | 16.4 EB05 12.8 · IC025 +3.4 3/3 methods agree | Not in label — unassessed | serious n=35 | not reported in cached trials |
| Substance use | 38 | 16.5 12.0–22.8ROR 16.5 · calibrated p 0.006 ✓ | 15.9 EB05 12.0 · IC025 +3.2 3/3 methods agree | Reporting / coding artifact | serious n=29 | not reported in cached trials |
| Hangover | 84 | 15.9 12.8–19.7ROR 15.9 · calibrated p 0.006 ✓ | 15.4 EB05 12.8 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=41 | not reported in cached trials |
| Cervical spinal stenosis | 40 | 15.4 11.3–21.1ROR 15.5 · calibrated p 0.007 ✓ | 14.9 EB05 11.3 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=38 | not reported in cached trials |
| Terminal insomnia | 39 | 15.0 10.9–20.6ROR 15.0 · calibrated p 0.008 ✓ | 14.5 EB05 10.9 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | 100% consumer | not reported in cached trials |
| Jc polyomavirus test positive | 26 | 14.7 10.0–21.7ROR 14.7 · calibrated p 0.010 ✓ | 14.0 EB05 9.8 · IC025 +2.9 3/3 methods agree | Lab value / disease marker | serious n=16 | not reported in cached trials |
| Sleep talking | 37 | 14.4 10.4–20.0ROR 14.5 · calibrated p 0.010 ✓ | 13.9 EB05 10.3 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious n=22 | not reported in cached trials |
| Hypervigilance | 19 | 13.1 8.3–20.7ROR 13.1 · calibrated p 0.016 ✓ | 12.1 EB05 7.7 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | – | not reported in cached trials |
| Band sensation | 24 | 12.5 8.3–18.7ROR 12.5 · calibrated p 0.018 ✓ | 11.6 EB05 7.8 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | ♀ 100% (drug 70%) | not reported in cached trials |
| Sudden onset of sleep | 26 | 12.4 8.4–18.3ROR 12.4 · calibrated p 0.019 ✓ | 11.6 EB05 8.0 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=21 | not reported in cached trials |
| Feeling drunk | 135 | 12.0 10.1–14.2ROR 12.1 · calibrated p 0.017 ✓ | 11.7 EB05 10.1 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=63 | not reported in cached trials |
| Nasal septum deviation | 35 | 11.9 8.5–16.6ROR 11.9 · calibrated p 0.020 ✓ | 11.2 EB05 8.2 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=29 | not reported in cached trials |
| Polycystic ovaries | 27 | 11.4 7.8–16.7ROR 11.4 · calibrated p 0.025 ✓ | 10.6 EB05 7.3 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | ♀ 100% (drug 70%) | not reported in cached trials |
| Essential tremor | 19 | 11.3 7.2–17.8ROR 11.3 · calibrated p 0.028 ✓ | 10.1 EB05 6.4 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | – | not reported in cached trials |
| Neurogenic bladder | 35 | 11.0 7.8–15.3ROR 11.0 · calibrated p 0.027 ✓ | 10.3 EB05 7.5 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=31 | not reported in cached trials |
| Mitral valve prolapse | 26 | 10.3 7.0–15.2ROR 10.3 · calibrated p 0.035 ✓ | 9.4 EB05 6.5 · IC025 +2.5 3/3 methods agree | Labeled adverse reaction exact term | serious n=23 · ♀ 100% (drug 70%) | not reported in cached trials |
| Complex regional pain syndrome | 23 | 10.2 6.8–15.5ROR 10.3 · calibrated p 0.037 ✓ | 9.2 EB05 6.2 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=21 | not reported in cached trials |
| Impulse-control disorder | 31 | 10.0 7.0–14.2ROR 10.0 · calibrated p 0.038 ✓ | 9.2 EB05 6.6 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=23 · ♀ 100% (drug 70%) · 100% consumer | not reported in cached trials |
| B-lymphocyte count decreased | 20 | 9.8 6.3–15.3ROR 9.8 · calibrated p 0.043 ✓ | 8.7 EB05 5.7 · IC025 +2.2 3/3 methods agree | Lab value / disease marker | – | not reported in cached trials |
| Drug tolerance | 75 | 9.8 7.8–12.3ROR 9.8 · calibrated p 0.037 ✓ | 9.4 EB05 7.7 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=50 · ♀ 47% (drug 70%) | not reported in cached trials |
| Wisdom teeth removal | 19 | 9.7 6.2–15.2ROR 9.7 · calibrated p 0.045 ✓ | 8.5 EB05 5.5 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | – | not reported in cached trials |
| Post-traumatic stress disorder | 98 | 9.7 7.9–11.8ROR 9.7 · calibrated p 0.038 ✓ | 9.3 EB05 7.8 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=85 | not reported in cached trials |
| Major depression | 106 | 9.6 7.9–11.6ROR 9.6 · calibrated p 0.039 ✓ | 9.3 EB05 7.8 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 9.5 | NCT01121536: 1/863 (0.1%) on Modafinil (serious AE) |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Modafinil 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 (1 of 40 signal terms matched).
- NCT01121536 — Extension Study of the Safety and Efficacy of Armodafinil Treatment as Adjunctive Therapy in Adults With Major (N=867, PHASE3; 29 AE terms posted; arms: Armodafinil 150-200 mg/Day)
- NCT01072630 — Study to Evaluate the Efficacy and Safety of Armodafinil Treatment as Adjunctive Therapy in Adults With Major (N=492, PHASE3; 20 AE terms posted; arms: Armodafinil 150 mg/Day; Armodafinil 200 mg/Day; Placebo)
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 |
|---|---|---|---|---|---|---|
| Fatigue (tiredness) | 2,945 | 2.5 2.4–2.6ROR 2.6 · calibrated p 0.759 | 2.5 EB05 2.4 · IC025 +1.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.4 | not reported in cached trials |
| Nausea | 2,248 | 1.9 1.8–1.9ROR 1.9 · calibrated p 0.905 | 1.9 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 2.0 | NCT01072630: 4/30 (13.3%) on Modafinil; 5/229 (2.2%) control |
| Drug ineffective (drug did not work) | 2,139 | 1.1 1.0–1.1ROR 1.1 · calibrated p 0.350 | 1.1 EB05 1.0 · IC025 +0.0 | Reporting / coding artifact | serious PRR 1.2 | not reported in cached trials |
| Headache | 1,871 | 2.0 1.9–2.0ROR 2.0 · calibrated p 0.952 | 2.0 EB05 1.9 · IC025 +0.9 | Labeled adverse reaction exact term | serious PRR 2.2 | NCT01121536: 96/863 (11.1%) on Modafinil |
| Fall | 1,791 | 3.5 3.4–3.7ROR 3.7 · calibrated p 0.442 | 3.5 EB05 3.4 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.1 | not reported in cached trials |
| Depression | 1,617 | 4.6 4.4–4.9ROR 4.8 · calibrated p 0.252 | 4.6 EB05 4.4 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.6 | NCT01121536: 1/863 (0.1%) on Modafinil (serious AE) |
| Anxiety | 1,501 | 3.5 3.3–3.6ROR 3.6 · calibrated p 0.468 | 3.4 EB05 3.3 · IC025 +1.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.4 | NCT01072630: 2/30 (6.7%) on Modafinil; 6/229 (2.6%) control |
| Somnolence (drowsiness) | 1,418 | 4.6 4.4–4.9ROR 4.8 · calibrated p 0.257 | 4.6 EB05 4.4 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.2 | not reported in cached trials |
| Dizziness | 1,405 | 1.8 1.8–1.9ROR 1.9 · calibrated p 0.879 | 1.8 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 1.8 | NCT01072630: 3/30 (10.0%) on Modafinil; 2/229 (0.9%) control |
| Pain | 1,292 | 1.4 1.3–1.4ROR 1.4 · calibrated p 0.568 | 1.4 EB05 1.3 · IC025 +0.4 | Labeled adverse reaction exact term | serious PRR 1.4 | NCT01072630: 1/231 (0.4%) on Modafinil (serious AE) |
| Insomnia (trouble sleeping) | 1,148 | 2.8 2.7–3.0ROR 2.9 · calibrated p 0.664 | 2.8 EB05 2.7 · IC025 +1.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.8 | NCT01121536: 49/863 (5.7%) on Modafinil |
| Condition aggravated | 1,132 | 2.5 2.3–2.6ROR 2.5 · calibrated p 0.810 | 2.4 EB05 2.3 · IC025 +1.2 3/3 methods agree | Reporting / coding artifact | serious PRR 2.5 | not reported in cached trials |
| Feeling abnormal | 1,118 | 3.0 2.9–3.2ROR 3.1 · calibrated p 0.589 | 3.0 EB05 2.9 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious PRR 3.2 | not reported in cached trials |
| Weight decreased (weight loss) | 1,107 | 2.6 2.5–2.8ROR 2.7 · calibrated p 0.750 | 2.6 EB05 2.5 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 2.9 | not reported in cached trials |
| Asthenia (weakness) | 1,079 | 1.9 1.8–2.0ROR 1.9 · calibrated p 0.893 | 1.9 EB05 1.8 · IC025 +0.8 | Labeled adverse reaction exact term | serious PRR 1.8 | not reported in cached trials |
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.
- Cataplexy — n=280, PRR 159.5
- Pre-existing condition improved — n=556, PRR 63.1
- Periodic limb movement disorder — n=32, PRR 62.0
- Parasomnia — n=53, PRR 53.4
- Sleep-related eating disorder — n=65, PRR 48.5
- Sleep attacks — n=28, PRR 41.0
- Sleep paralysis — n=79, PRR 37.2
- Abnormal sleep-related event — n=64, PRR 33.1
- Snoring — n=164, PRR 29.7
- Enuresis — n=161, PRR 27.1
✓ A hand-written Bradford Hill causality assessment exists for this drug: Modafinil ↔ Suicidal ideation.
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 Modafinil?
In FDA FAERS, the most frequently co-reported reaction terms for Modafinil are fatigue, nausea, headache, fall, depression, anxiety. 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 Modafinil have an FDA boxed warning?
No. The FDA label retrieved for Modafinil has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Modafinil 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 1d4c6858-5b2f-f216-e063-6394a90aad5d, effective 20260316; matched on
openfda.generic_name.exact:"MODAFINIL") - 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, 1,195 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
MODAFINIL, results-bearing studies sorted by enrollment)
Page generated 2026-10-14. 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.