Drug · FAERS side-effect profile with label screen
Acetaminophen and Diphenhydramine side effects: what 4,728 FDA adverse event reports show
Drug class
Not stated in label
Label matched
Acetaminophen (Acetaminophen)
closest FDA label found for this product string; brand list suppressed because the label is a related product, not an exact match
Who reports
4,728 reports · 58% serious · 322 with death outcome · 65% female
openFDA FAERS counts, all years, deduplication not applied
Used for
temporarily relieves minor aches and pains due to: headache muscular aches backache minor pain of arthritis the common cold toothache premenstrual and menstrual cramps temporarily reduces fever
FDA label, Indications and Usage
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
Reporting / coding artifact 3Lab value / disease marker 2Not in label — unassessed 35
What the badges mean
- 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. 407 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 |
|---|---|---|---|---|---|---|
| Acute hepatic failure | 86 | 28.2 22.8–34.8ROR 28.7 · χ² 2,215 / p <1e-300 | 27.9 EB05 23.3 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious PRR 27.9 | no trial data cached |
| Drug administration error | 89 | 12.7 10.3–15.6ROR 12.9 · χ² 946 / p 4e-208 | 12.5 EB05 10.5 · IC025 +3.2 3/3 methods agree | Reporting / coding artifact | serious PRR 7.1 · 91% consumer | no trial data cached |
| Product administration error | 49 | 10.9 8.2–14.4ROR 11.0 · χ² 430 / p 8e-96 | 10.5 EB05 8.1 · IC025 +2.8 3/3 methods agree | Reporting / coding artifact | serious PRR 6.0 · 84% consumer | no trial data cached |
| Intentional overdose | 115 | 8.0 6.7–9.6ROR 8.2 · χ² 699 / p 3e-154 | 7.8 EB05 6.7 · IC025 +2.6 3/3 methods agree | Reporting / coding artifact | serious PRR 8.3 | no trial data cached |
| Atelectasis | 17 | 7.8 4.8–12.5ROR 7.8 · χ² 94 / p 2e-22 | 6.7 EB05 4.3 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 7.8 | no trial data cached |
| Brain oedema | 21 | 7.4 4.8–11.3ROR 7.4 · χ² 109 / p 7e-26 | 6.5 EB05 4.4 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 7.4 | no trial data cached |
| Hepatic encephalopathy | 14 | 6.6 3.9–11.2ROR 6.7 · χ² 62 / p 2e-15 | 5.6 EB05 3.5 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 6.6 | no trial data cached |
| Hemiparesis | 24 | 6.2 4.2–9.3ROR 6.3 · χ² 100 / p 6e-24 | 5.6 EB05 4.0 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 5.3 | no trial data cached |
| Coagulopathy | 22 | 5.9 3.9–8.9ROR 5.9 · χ² 84 / p 2e-20 | 5.3 EB05 3.7 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 6.1 · 86% consumer | no trial data cached |
| Seasonal allergy | 18 | 5.7 3.6–9.0ROR 5.7 · χ² 64 / p 5e-16 | 5.0 EB05 3.3 · IC025 +1.5 3/3 methods agree | Not in label — unassessed | serious n=9 | no trial data cached |
| Suicide attempt | 76 | 5.5 4.4–6.9ROR 5.6 · χ² 279 / p 6e-63 | 5.4 EB05 4.4 · IC025 +2.0 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 | no trial data cached |
| Ligament sprain | 12 | 5.4 3.1–9.5ROR 5.4 · χ² 39 / p 3e-10 | 4.5 EB05 2.8 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious n=8 | no trial data cached |
| Carpal tunnel syndrome | 17 | 5.4 3.3–8.6ROR 5.4 · χ² 56 / p 3e-14 | 4.7 EB05 3.1 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 5.8 | no trial data cached |
| Subarachnoid haemorrhage | 12 | 5.2 3.0–9.2ROR 5.2 · χ² 37 / p 7e-10 | 4.4 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 5.2 | no trial data cached |
| Blood iron decreased | 13 | 4.9 2.8–8.4ROR 4.9 · χ² 36 / p 8e-10 | 4.2 EB05 2.6 · IC025 +1.2 3/3 methods agree | Lab value / disease marker | serious PRR 5.1 | no trial data cached |
| Increased tendency to bruise | 10 | 4.8 2.6–8.9ROR 4.8 · χ² 26 / p 1e-7 | 4.0 EB05 2.4 · IC025 +0.9 3/3 methods agree | Not in label — unassessed | serious n=9 | no trial data cached |
| Initial insomnia | 11 | 4.8 2.6–8.6ROR 4.8 · χ² 29 / p 3e-8 | 4.1 EB05 2.4 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | – | no trial data cached |
| Hepatic failure | 32 | 4.7 3.3–6.6ROR 4.7 · χ² 89 / p 2e-21 | 4.4 EB05 3.3 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 · ♀ 88% (drug 65%) | no trial data cached |
| Hypercholesterolaemia | 10 | 4.6 2.5–8.6ROR 4.6 · χ² 25 / p 3e-7 | 3.9 EB05 2.3 · IC025 +0.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Vitamin d deficiency | 10 | 4.5 2.4–8.5ROR 4.6 · χ² 24 / p 4e-7 | 3.8 EB05 2.3 · IC025 +0.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Skin laceration | 11 | 4.5 2.5–8.2ROR 4.5 · χ² 27 / p 1e-7 | 3.9 EB05 2.3 · IC025 +0.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.1 | no trial data cached |
| Rotator cuff syndrome | 13 | 4.5 2.6–7.7ROR 4.5 · χ² 32 / p 9e-9 | 3.9 EB05 2.5 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 | no trial data cached |
| Acute respiratory failure | 19 | 4.4 2.8–6.9ROR 4.4 · χ² 47 / p 4e-12 | 4.0 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Transaminases increased | 22 | 4.4 2.9–6.7ROR 4.4 · χ² 54 / p 9e-14 | 4.0 EB05 2.8 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 | no trial data cached |
| Mitral valve incompetence | 11 | 4.3 2.4–7.8ROR 4.3 · χ² 25 / p 3e-7 | 3.7 EB05 2.2 · IC025 +0.9 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Abnormal dreams | 27 | 4.3 3.0–6.3ROR 4.3 · χ² 65 / p 3e-16 | 4.0 EB05 2.9 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 3.4 · 96% consumer | no trial data cached |
| Candida infection (yeast infection) | 16 | 4.3 2.6–6.9ROR 4.3 · χ² 37 / p 7e-10 | 3.8 EB05 2.5 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 4.9 | no trial data cached |
| Liver injury | 23 | 4.2 2.8–6.3ROR 4.2 · χ² 53 / p 1e-13 | 3.9 EB05 2.8 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.4 | no trial data cached |
| Cerebrovascular accident (stroke) | 160 | 4.2 3.6–4.9ROR 4.3 · χ² 385 / p 4e-86 | 4.1 EB05 3.6 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 4.2 | no trial data cached |
| Mental status changes | 26 | 4.1 2.8–6.1ROR 4.2 · χ² 59 / p 8e-15 | 3.9 EB05 2.8 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 4.0 | no trial data cached |
| Decreased activity | 10 | 4.1 2.2–7.7ROR 4.1 · χ² 21 / p 3e-6 | 3.6 EB05 2.1 · IC025 +0.8 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 | no trial data cached |
| Insomnia (trouble sleeping) | 248 | 4.1 3.7–4.7ROR 4.3 · χ² 590 / p 1e-130 | 4.1 EB05 3.7 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 · 78% consumer | no trial data cached |
| Musculoskeletal chest pain | 14 | 4.0 2.4–6.8ROR 4.0 · χ² 29 / p 4e-8 | 3.6 EB05 2.3 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 4.5 | no trial data cached |
| Upper limb fracture | 18 | 4.0 2.5–6.3ROR 4.0 · χ² 37 / p 5e-10 | 3.7 EB05 2.5 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 | no trial data cached |
| Hypersomnia | 25 | 3.9 2.6–5.7ROR 3.9 · χ² 50 / p 6e-13 | 3.6 EB05 2.6 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 | no trial data cached |
| Full blood count decreased | 17 | 3.7 2.3–6.0ROR 3.7 · χ² 31 / p 1e-8 | 3.4 EB05 2.3 · IC025 +1.0 3/3 methods agree | Lab value / disease marker | serious PRR 4.7 | no trial data cached |
| Nocturia (night-time urination) | 10 | 3.7 2.0–6.8ROR 3.7 · χ² 17 / p 2e-5 | 3.2 EB05 1.9 · IC025 +0.6 | Not in label — unassessed | serious PRR 3.1 | no trial data cached |
| Intervertebral disc protrusion | 18 | 3.6 2.3–5.8ROR 3.7 · χ² 32 / p 8e-9 | 3.4 EB05 2.3 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 | no trial data cached |
| Muscle spasticity | 10 | 3.6 1.9–6.6ROR 3.6 · χ² 16 / p 3e-5 | 3.2 EB05 1.9 · IC025 +0.6 | Not in label — unassessed | serious PRR 3.6 | no trial data cached |
| Amnesia (memory loss) | 51 | 3.5 2.6–4.5ROR 3.5 · χ² 87 / p 5e-21 | 3.4 EB05 2.7 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).
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) | 438 | 2.5 2.3–2.7ROR 2.7 · χ² 407 / p 8e-91 | 2.5 EB05 2.3 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 2.5 | no trial data cached |
| Dizziness | 264 | 2.4 2.1–2.6ROR 2.4 · χ² 208 / p 2e-47 | 2.3 EB05 2.1 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 2.2 · 74% consumer | no trial data cached |
| Insomnia (trouble sleeping) | 248 | 4.1 3.7–4.7ROR 4.3 · χ² 590 / p 1e-130 | 4.1 EB05 3.7 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 3.5 · 78% consumer | no trial data cached |
| Asthenia (weakness) | 215 | 2.5 2.2–2.9ROR 2.6 · χ² 202 / p 5e-46 | 2.5 EB05 2.3 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 2.3 | no trial data cached |
| Fall | 188 | 2.5 2.2–2.9ROR 2.6 · χ² 171 / p 2e-39 | 2.5 EB05 2.2 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 2.4 | no trial data cached |
| Arthralgia (joint pain) | 164 | 1.8 1.5–2.0ROR 1.8 · χ² 53 / p 1e-13 | 1.8 EB05 1.5 · IC025 +0.5 | Not in label — unassessed | serious PRR 1.9 · 72% consumer | no trial data cached |
| Cerebrovascular accident (stroke) | 160 | 4.2 3.6–4.9ROR 4.3 · χ² 385 / p 4e-86 | 4.1 EB05 3.6 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 4.2 | no trial data cached |
| Constipation | 151 | 3.1 2.6–3.6ROR 3.2 · χ² 214 / p 1e-48 | 3.1 EB05 2.7 · IC025 +1.3 3/3 methods agree | Not in label — unassessed | serious PRR 2.8 · 76% consumer | no trial data cached |
| Decreased appetite (loss of appetite) | 126 | 2.4 2.0–2.9ROR 2.4 · χ² 104 / p 1e-24 | 2.4 EB05 2.1 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 2.0 · 70% consumer | no trial data cached |
| Overdose | 122 | 2.5 2.1–3.0ROR 2.5 · χ² 109 / p 8e-26 | 2.5 EB05 2.1 · IC025 +1.0 3/3 methods agree | Reporting / coding artifact | serious PRR 2.7 | no trial data cached |
| Intentional overdose | 115 | 8.0 6.7–9.6ROR 8.2 · χ² 699 / p 3e-154 | 7.8 EB05 6.7 · IC025 +2.6 3/3 methods agree | Reporting / coding artifact | serious PRR 8.3 | no trial data cached |
| Feeling abnormal | 105 | 1.9 1.6–2.3ROR 2.0 · χ² 47 / p 4e-12 | 1.9 EB05 1.6 · IC025 +0.6 | Not in label — unassessed | serious PRR 2.6 · 74% consumer | no trial data cached |
| Muscle spasms | 105 | 2.5 2.1–3.1ROR 2.6 · χ² 97 / p 4e-23 | 2.5 EB05 2.1 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 2.9 | no trial data cached |
| Somnolence (drowsiness) | 104 | 2.3 1.9–2.8ROR 2.3 · χ² 75 / p 2e-18 | 2.3 EB05 1.9 · IC025 +0.9 | Not in label — unassessed | serious PRR 1.9 | no trial data cached |
| Incorrect dose administered | 102 | 2.0 1.7–2.4ROR 2.0 · χ² 51 / p 4e-13 | 2.0 EB05 1.7 · IC025 +0.7 | Reporting / coding artifact | serious PRR 1.9 · 87% consumer | no trial data cached |
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.
- Acute hepatic failure — n=86, PRR 28.2
- Brain oedema — n=21, PRR 7.4
- Hemiparesis — n=24, PRR 6.2
- Coagulopathy — n=22, PRR 5.9
- Suicide attempt — n=76, PRR 5.5
- Hepatic failure — n=32, PRR 4.7
- Transaminases increased — n=22, PRR 4.4
- Abnormal dreams — n=27, PRR 4.3
- Liver injury — n=23, PRR 4.2
- Cerebrovascular accident — n=160, PRR 4.2
✓ A hand-written Bradford Hill causality assessment exists for this drug: Acetaminophen (paracetamol) ↔ Liver injury / hepatotoxicity.
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 Acetaminophen and Diphenhydramine?
In FDA FAERS, the most frequently co-reported reaction terms for Acetaminophen and Diphenhydramine are fatigue, dizziness, insomnia, asthenia, fall, arthralgia. 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 Acetaminophen and Diphenhydramine have an FDA boxed warning?
No. The FDA label retrieved for Acetaminophen and Diphenhydramine has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Acetaminophen and Diphenhydramine 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 004c39cd-b4f4-1cae-e063-6394a90a0697, effective 20251003; matched on
openfda.generic_name.exact:"ACETAMINOPHEN") - 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, 447 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
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.