Drug · FAERS side-effect profile with label screen
Guaifenesin and Dextromethorphan Hydrobromide side effects: what 7,320 FDA adverse event reports show
Drug class
Expectorant
FDA label (Established Pharmacologic Class)
Brand names
Mucus Relief
openFDA label
Who reports
7,320 reports · 25% serious · 95 with death outcome · 66% female
openFDA FAERS counts, all years, deduplication not applied
Used for
(S) helps loosen phlegm (mucus) and thin bronchial secretions to rid the bronchial passageways of bothersome mucus and make coughs more productive
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 10Lab value / disease marker 1No label text to screen 29
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.
- No label text to screen No validated FDA label was retrievable for this product, so the screen could not run. Disproportionality only.
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. 173 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 |
|---|---|---|---|---|---|---|
| Accidental overdose | 543 | 43.2 39.8–46.8ROR 46.5 · χ² 22,027 / p <1e-300 | 42.5 EB05 39.6 · IC025 +5.2 3/3 methods agree | Reporting / coding artifact | serious PRR 14.4 · 99% consumer | no trial data cached |
| Incorrect product administration duration | 222 | 31.7 27.8–36.1ROR 32.6 · χ² 6,494 / p <1e-300 | 31.2 EB05 27.9 · IC025 +4.7 3/3 methods agree | Reporting / coding artifact | serious n=10 · 99% consumer | no trial data cached |
| Drug effective for unapproved indication | 182 | 17.9 15.5–20.7ROR 18.4 · χ² 2,880 / p <1e-300 | 17.8 EB05 15.7 · IC025 +3.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | 100% consumer | no trial data cached |
| Incorrect drug administration duration | 155 | 15.6 13.4–18.3ROR 16.0 · χ² 2,100 / p <1e-300 | 15.5 EB05 13.6 · IC025 +3.6 3/3 methods agree | Reporting / coding artifact | serious PRR 27.8 · 97% consumer | no trial data cached |
| Expired product administered | 170 | 14.7 12.7–17.1ROR 15.1 · χ² 2,156 / p <1e-300 | 14.6 EB05 12.9 · IC025 +3.6 3/3 methods agree | Reporting / coding artifact | serious n=22 · 98% consumer | no trial data cached |
| Product use complaint | 65 | 12.1 9.5–15.4ROR 12.2 · χ² 646 / p 1e-142 | 11.8 EB05 9.5 · IC025 +3.1 3/3 methods agree | Reporting / coding artifact | serious n=9 · 97% consumer | no trial data cached |
| Euphoric mood | 40 | 11.2 8.2–15.2ROR 11.2 · χ² 358 / p 3e-80 | 10.7 EB05 8.0 · IC025 +2.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious n=15 · 95% consumer | no trial data cached |
| Feeling jittery | 43 | 6.5 4.8–8.7ROR 6.5 · χ² 193 / p 4e-44 | 6.1 EB05 4.7 · IC025 +2.1 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious n=15 · 100% consumer | no trial data cached |
| Retching | 43 | 5.8 4.3–7.8ROR 5.8 · χ² 166 / p 3e-38 | 5.5 EB05 4.2 · IC025 +1.9 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 9.7 · 90% consumer | no trial data cached |
| Mydriasis | 25 | 5.6 3.8–8.3ROR 5.6 · χ² 90 / p 1e-21 | 5.1 EB05 3.6 · IC025 +1.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 11.2 · 100% consumer | no trial data cached |
| Overdose | 390 | 5.2 4.7–5.7ROR 5.4 · χ² 1,316 / p 2e-288 | 5.1 EB05 4.7 · IC025 +2.2 3/3 methods agree | Reporting / coding artifact | serious PRR 2.4 · 98% consumer | no trial data cached |
| Dizziness | 864 | 5.0 4.7–5.3ROR 5.5 · χ² 2,802 / p <1e-300 | 5.0 EB05 4.7 · IC025 +2.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.4 · 94% consumer | no trial data cached |
| Respiratory tract congestion | 27 | 4.9 3.3–7.1ROR 4.9 · χ² 79 / p 3e-19 | 4.5 EB05 3.3 · IC025 +1.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 12.4 · 85% consumer | no trial data cached |
| Dry throat | 17 | 4.8 3.0–7.7ROR 4.8 · χ² 47 / p 3e-12 | 4.3 EB05 2.8 · IC025 +1.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | – | no trial data cached |
| Choking | 31 | 4.6 3.2–6.5ROR 4.6 · χ² 83 / p 4e-20 | 4.3 EB05 3.2 · IC025 +1.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.3 · 94% consumer | no trial data cached |
| Product complaint | 39 | 4.5 3.3–6.1ROR 4.5 · χ² 102 / p 3e-24 | 4.3 EB05 3.3 · IC025 +1.6 3/3 methods agree | Reporting / coding artifact | serious n=3 · 100% consumer | no trial data cached |
| Seasonal allergy | 22 | 4.5 2.9–6.8ROR 4.5 · χ² 56 / p 4e-14 | 4.1 EB05 2.9 · IC025 +1.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious n=10 · 80% consumer | no trial data cached |
| Hallucination (hallucinations) | 114 | 4.4 3.6–5.2ROR 4.4 · χ² 292 / p 8e-66 | 4.3 EB05 3.7 · IC025 +1.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 11.9 · 94% consumer | no trial data cached |
| Somnolence (drowsiness) | 300 | 4.3 3.8–4.8ROR 4.4 · χ² 756 / p 9e-167 | 4.2 EB05 3.9 · IC025 +1.9 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.5 · 93% consumer | no trial data cached |
| Product use in unapproved indication | 357 | 4.2 3.8–4.6ROR 4.4 · χ² 872 / p 5e-192 | 4.2 EB05 3.8 · IC025 +1.9 3/3 methods agree | Reporting / coding artifact | serious PRR 2.3 · 97% consumer | no trial data cached |
| Anosmia (loss of smell) | 21 | 4.1 2.7–6.4ROR 4.2 · χ² 47 / p 3e-12 | 3.8 EB05 2.7 · IC025 +1.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious n=3 · 90% consumer | no trial data cached |
| Disorientation | 57 | 4.1 3.2–5.3ROR 4.1 · χ² 131 / p 1e-30 | 4.0 EB05 3.2 · IC025 +1.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.5 · 95% consumer | no trial data cached |
| Haemoptysis | 40 | 4.1 3.0–5.6ROR 4.1 · χ² 91 / p 8e-22 | 3.9 EB05 3.0 · IC025 +1.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 9.5 · 92% consumer | no trial data cached |
| Ageusia (loss of taste) | 34 | 3.9 2.8–5.4ROR 3.9 · χ² 70 / p 3e-17 | 3.7 EB05 2.8 · IC025 +1.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.2 · 91% consumer | no trial data cached |
| Nervousness | 69 | 3.8 3.0–4.8ROR 3.8 · χ² 138 / p 5e-32 | 3.7 EB05 3.0 · IC025 +1.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.2 · 94% consumer | no trial data cached |
| Secretion discharge | 15 | 3.5 2.1–5.8ROR 3.5 · χ² 24 / p 5e-7 | 3.2 EB05 2.1 · IC025 +0.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.1 | no trial data cached |
| Feeling abnormal | 291 | 3.5 3.1–3.9ROR 3.6 · χ² 514 / p 5e-114 | 3.4 EB05 3.1 · IC025 +1.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.0 · 91% consumer | no trial data cached |
| Pulmonary congestion | 16 | 3.5 2.1–5.7ROR 3.5 · χ² 26 / p 2e-7 | 3.2 EB05 2.1 · IC025 +0.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.9 | no trial data cached |
| Drug ineffective for unapproved indication | 67 | 3.4 2.7–4.4ROR 3.5 · χ² 114 / p 7e-27 | 3.4 EB05 2.8 · IC025 +1.4 3/3 methods agree | Reporting / coding artifact | serious PRR 0.5 · 100% consumer | no trial data cached |
| Hypoaesthesia oral | 18 | 3.4 2.2–5.4ROR 3.4 · χ² 29 / p 5e-8 | 3.2 EB05 2.2 · IC025 +0.9 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.8 | no trial data cached |
| Disease recurrence | 57 | 3.4 2.6–4.4ROR 3.4 · χ² 95 / p 8e-23 | 3.3 EB05 2.7 · IC025 +1.3 3/3 methods agree | Reporting / coding artifact | serious PRR 1.1 · 91% consumer | no trial data cached |
| Brain fog | 17 | 3.3 2.1–5.4ROR 3.3 · χ² 26 / p 2e-7 | 3.1 EB05 2.1 · IC025 +0.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.5 | no trial data cached |
| Presyncope (near-fainting) | 28 | 3.3 2.3–4.8ROR 3.3 · χ² 43 / p 3e-11 | 3.2 EB05 2.3 · IC025 +1.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.9 · 85% consumer | no trial data cached |
| Aphonia | 16 | 3.3 2.0–5.4ROR 3.3 · χ² 23 / p 7e-7 | 3.1 EB05 2.0 · IC025 +0.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.4 | no trial data cached |
| Psychomotor hyperactivity | 19 | 3.3 2.1–5.1ROR 3.3 · χ² 28 / p 7e-8 | 3.1 EB05 2.1 · IC025 +0.9 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.2 | no trial data cached |
| Blood pressure increased | 174 | 3.3 2.8–3.8ROR 3.3 · χ² 271 / p 3e-61 | 3.2 EB05 2.8 · IC025 +1.4 3/3 methods agree | Lab value / disease marker | serious PRR 7.4 · 91% consumer | no trial data cached |
| Epistaxis (nosebleed) | 84 | 3.2 2.6–4.0ROR 3.2 · χ² 126 / p 2e-29 | 3.2 EB05 2.6 · IC025 +1.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.6 · 95% consumer | no trial data cached |
| Productive cough (cough with phlegm) | 53 | 3.2 2.5–4.2ROR 3.2 · χ² 78 / p 4e-19 | 3.1 EB05 2.5 · IC025 +1.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.6 | no trial data cached |
| Laryngitis | 12 | 3.2 1.8–5.6ROR 3.2 · χ² 16 / p 4e-5 | 2.9 EB05 1.8 · IC025 +0.6 | No label text to screen label has no adverse-reaction text | serious n=6 | no trial data cached |
| Palpitations (pounding heartbeat) | 127 | 3.1 2.6–3.7ROR 3.1 · χ² 181 / p 2e-41 | 3.1 EB05 2.7 · IC025 +1.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.4 · 89% consumer | 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 |
|---|---|---|---|---|---|---|
| Drug ineffective (drug did not work) | 989 | 2.2 2.0–2.3ROR 2.3 · χ² 649 / p 2e-143 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Reporting / coding artifact | serious PRR 0.9 · 96% consumer | no trial data cached |
| Dizziness | 864 | 5.0 4.7–5.3ROR 5.5 · χ² 2,802 / p <1e-300 | 5.0 EB05 4.7 · IC025 +2.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.4 · 94% consumer | no trial data cached |
| Diarrhoea (diarrhea) | 641 | 2.9 2.7–3.1ROR 3.0 · χ² 794 / p 4e-175 | 2.8 EB05 2.7 · IC025 +1.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 2.5 · 90% consumer | no trial data cached |
| Accidental overdose | 543 | 43.2 39.8–46.8ROR 46.5 · χ² 22,027 / p <1e-300 | 42.5 EB05 39.6 · IC025 +5.2 3/3 methods agree | Reporting / coding artifact | serious PRR 14.4 · 99% consumer | no trial data cached |
| Nausea | 515 | 1.9 1.7–2.0ROR 1.9 · χ² 215 / p 5e-49 | 1.9 EB05 1.7 · IC025 +0.8 | No label text to screen label has no adverse-reaction text | serious PRR 3.0 · 91% consumer | no trial data cached |
| Overdose | 390 | 5.2 4.7–5.7ROR 5.4 · χ² 1,316 / p 2e-288 | 5.1 EB05 4.7 · IC025 +2.2 3/3 methods agree | Reporting / coding artifact | serious PRR 2.4 · 98% consumer | no trial data cached |
| Product use in unapproved indication | 357 | 4.2 3.8–4.6ROR 4.4 · χ² 872 / p 5e-192 | 4.2 EB05 3.8 · IC025 +1.9 3/3 methods agree | Reporting / coding artifact | serious PRR 2.3 · 97% consumer | no trial data cached |
| Somnolence (drowsiness) | 300 | 4.3 3.8–4.8ROR 4.4 · χ² 756 / p 9e-167 | 4.2 EB05 3.9 · IC025 +1.9 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.5 · 93% consumer | no trial data cached |
| Headache | 293 | 1.3 1.2–1.5ROR 1.4 · χ² 26 / p 2e-7 | 1.3 EB05 1.2 · IC025 +0.2 | No label text to screen label has no adverse-reaction text | serious PRR 2.3 · 89% consumer | no trial data cached |
| Feeling abnormal | 291 | 3.5 3.1–3.9ROR 3.6 · χ² 514 / p 5e-114 | 3.4 EB05 3.1 · IC025 +1.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.0 · 91% consumer | no trial data cached |
| Vomiting | 288 | 1.8 1.6–2.0ROR 1.8 · χ² 96 / p 7e-23 | 1.8 EB05 1.6 · IC025 +0.6 | No label text to screen label has no adverse-reaction text | serious PRR 2.5 · 89% consumer | no trial data cached |
| Dyspnoea (shortness of breath) | 286 | 1.4 1.3–1.6ROR 1.5 · χ² 40 / p 1e-10 | 1.4 EB05 1.3 · IC025 +0.3 | No label text to screen label has no adverse-reaction text | serious PRR 2.5 · 81% consumer | no trial data cached |
| Insomnia (trouble sleeping) | 268 | 2.9 2.6–3.2ROR 2.9 · χ² 330 / p 4e-74 | 2.9 EB05 2.6 · IC025 +1.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.2 · 94% consumer | no trial data cached |
| Cough | 229 | 2.3 2.1–2.7ROR 2.4 · χ² 177 / p 9e-41 | 2.3 EB05 2.1 · IC025 +1.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.5 · 86% consumer | no trial data cached |
| Incorrect product administration duration | 222 | 31.7 27.8–36.1ROR 32.6 · χ² 6,494 / p <1e-300 | 31.2 EB05 27.9 · IC025 +4.7 3/3 methods agree | Reporting / coding artifact | serious n=10 · 99% consumer | no trial data cached |
Unlabeled candidate signals
Every screened signal with n ≥ 20 was either labeled, an indication term, or an artifact pattern — no unlabeled candidate stood out in the top signals.
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 Guaifenesin?
In FDA FAERS, the most frequently co-reported reaction terms for Guaifenesin are dizziness, diarrhoea, nausea, somnolence, headache, feeling abnormal. 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 Guaifenesin have an FDA boxed warning?
No. The FDA label retrieved for Guaifenesin has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Guaifenesin 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 c648e711-e944-4574-83b3-ccce8732384e, effective 20250602; matched on
openfda.generic_name.exact:"GUAIFENESIN" AND openfda.product_type:"HUMAN PRESCRIPTION DRUG") - 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, 213 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.