Drug · FAERS side-effect profile with label screen
Ondansetron side effects: what 108,583 FDA adverse event reports show
Drug class
Serotonin-3 Receptor Antagonist
FDA label (Established Pharmacologic Class) · compare the class
Who reports
108,583 reports · 81% serious · 13,975 with death outcome · 61% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Ondansetron orally disintegrating tablets are indicated for the prevention of nausea and vomiting associated with: highly emetogenic cancer chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 initial and repeat courses of moderately em.
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
Labeled adverse reaction 5Labeled (related wording) 2Reporting / coding artifact 5Lab value / disease marker 1Not in label — unassessed 27
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.
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- 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). 1,163 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 |
|---|---|---|---|---|---|---|
| Appendicolith | 266 | 462.4 370.0–577.8ROR 463.5 · calibrated p 2e-13 ✓ | 133.8 EB05 120.9 · IC025 +6.6 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.1 (1.8–2.4) | Not in label — unassessed | serious n=266 · ♀ 0% (drug 61%) · 100% clinician | no trial arm names this drug |
| Sleep disorder therapy | 110 | 281.6 209.8–378.1ROR 281.9 · calibrated p 4e-11 ✓ | 111.7 EB05 95.3 · IC025 +5.9 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.6–2.4) | Reporting / coding artifact | serious n=110 · ♀ 0% (drug 61%) · 100% clinician | no trial arm names this drug |
| Antacid therapy | 64 | 220.5 153.8–316.1ROR 220.6 · calibrated p 6e-10 ✓ | 99.5 EB05 80.6 · IC025 +5.4 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.4–2.5) | Reporting / coding artifact | serious n=64 · ♀ 0% (drug 61%) · 100% clinician | no trial arm names this drug |
| Analgesic therapy | 111 | 109.5 86.7–138.4ROR 109.6 · calibrated p 8e-8 ✓ | 69.0 EB05 58.9 · IC025 +5.4 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.6–2.4) | Reporting / coding artifact | serious n=111 · ♀ 0% (drug 61%) · 100% clinician | no trial arm names this drug |
| Drug therapy | 98 | 85.2 67.1–108.1ROR 85.2 · calibrated p 5e-7 ✓ | 58.4 EB05 49.3 · IC025 +5.2 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.5–2.5) | Reporting / coding artifact | serious n=98 · ♀ 0% (drug 61%) · 100% clinician | no trial arm names this drug |
| Anticoagulant therapy | 67 | 61.3 46.6–80.8ROR 61.4 · calibrated p 5e-6 ✓ | 46.0 EB05 37.5 · IC025 +4.7 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.4–2.5) | Reporting / coding artifact | serious n=67 · ♀ 0% (drug 61%) · 100% clinician | no trial arm names this drug |
| Neurologic neglect syndrome | 130 | 58.2 47.8–70.9ROR 58.3 · calibrated p 6e-6 ✓ | 44.5 EB05 38.4 · IC025 +5.0 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.5–2.3) | Not in label — unassessed | serious n=130 · ♀ 100% (drug 61%) · 100% clinician | no trial arm names this drug |
| Left-to-right cardiac shunt | 68 | 57.3 43.7–75.1ROR 57.3 · calibrated p 8e-6 ✓ | 43.7 EB05 35.7 · IC025 +4.7 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.8 (1.4–2.4) | Not in label — unassessed | serious n=68 · ♀ 0% (drug 61%) · 100% consumer | no trial arm names this drug |
| Carotid artery thrombosis | 138 | 37.1 30.9–44.5ROR 37.1 · calibrated p 9e-5 ✓ | 31.1 EB05 26.9 · IC025 +4.5 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.6–2.3) | Not in label — unassessed | serious n=138 · ♀ 100% (drug 61%) · 100% clinician | no trial arm names this drug |
| Chronic kidney disease-mineral and bone disorder | 139 | 28.5 23.9–34.1ROR 28.6 · calibrated p 4e-4 ✓ | 24.9 EB05 21.6 · IC025 +4.2 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.2 (1.8–2.6) | Not in label — unassessed | serious n=139 | no trial arm names this drug |
| Temperature regulation disorder | 244 | 24.2 21.2–27.6ROR 24.2 · calibrated p 8e-4 ✓ | 21.5 EB05 19.3 · IC025 +4.2 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.7–2.3) | Not in label — unassessed | serious n=239 · ♀ 100% (drug 61%) | no trial arm names this drug |
| Adjustment disorder | 136 | 22.4 18.7–26.7ROR 22.4 · calibrated p 0.001 ✓ | 20.1 EB05 17.4 · IC025 +3.9 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.6–2.3) | Not in label — unassessed | serious n=135 · ♀ 100% (drug 61%) · 100% clinician | no trial arm names this drug |
| Aplastic anaemia | 534 | 21.8 19.9–23.8ROR 21.9 · calibrated p 0.001 ✓ | 19.6 EB05 18.3 · IC025 +4.1 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.8–2.3) | Not in label — unassessed | serious n=534 · 95% clinician | no trial arm names this drug |
| Nephrogenic anaemia | 451 | 20.5 18.6–22.6ROR 20.6 · calibrated p 0.002 ✓ | 18.6 EB05 17.2 · IC025 +4.0 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.1 (1.9–2.4) | Not in label — unassessed | serious n=451 | no trial arm names this drug |
| Hyperparathyroidism secondary | 220 | 18.3 15.9–21.0ROR 18.3 · calibrated p 0.003 ✓ | 16.7 EB05 15.0 · IC025 +3.8 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.1 (1.8–2.5) | Not in label — unassessed | serious n=220 | no trial arm names this drug |
| Hyperphosphataemia | 183 | 18.2 15.6–21.1ROR 18.2 · calibrated p 0.003 ✓ | 16.6 EB05 14.7 · IC025 +3.8 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.6–2.3) | Not in label — unassessed | serious n=183 · ♀ 0% (drug 61%) · 100% clinician | no trial arm names this drug |
| Blood phosphorus increased | 225 | 17.3 15.1–19.8ROR 17.3 · calibrated p 0.004 ✓ | 15.9 EB05 14.2 · IC025 +3.7 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.1 (1.8–2.4) | Lab value / disease marker | serious n=218 · ♀ 0% (drug 61%) · 92% clinician | no trial arm names this drug |
| Anaesthetic complication neurological | 65 | 14.7 11.5–19.0ROR 14.8 · calibrated p 0.008 ✓ | 13.6 EB05 11.0 · IC025 +3.2 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 4.4 (3.1–6.2) | Not in label — unassessed | serious n=65 · 100% clinician | no trial arm names this drug |
| Febrile neutropenia | 4,690 | 14.6 14.2–15.1ROR 15.3 · calibrated p 0.006 ✓ | 13.7 EB05 13.3 · IC025 +3.7 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.8 (1.8–1.9) | Not in label — unassessed | age-adj. PRR 13.5 · serious PRR 9.8 · 95% clinician | no trial arm names this drug |
| Rebound acid hypersecretion | 212 | 14.3 12.4–16.4ROR 14.3 · calibrated p 0.009 ✓ | 13.3 EB05 11.9 · IC025 +3.5 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.2 (1.8–2.6) | Not in label — unassessed | serious n=212 | no trial arm names this drug |
| Platelet transfusion | 77 | 12.3 9.8–15.5ROR 12.3 · calibrated p 0.016 ✓ | 11.4 EB05 9.4 · IC025 +3.1 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.1 (1.6–2.8) | Not in label — unassessed | serious n=77 · ♀ 0% (drug 61%) · 100% clinician | no trial arm names this drug |
| Neutropenic sepsis | 425 | 12.1 11.0–13.4ROR 12.2 · calibrated p 0.016 ✓ | 11.4 EB05 10.5 · IC025 +3.3 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.7–2.2) | Not in label — unassessed | serious PRR 8.2 · 93% clinician | no trial arm names this drug |
| Neutropenic colitis | 121 | 12.0 10.0–14.4ROR 12.0 · calibrated p 0.018 ✓ | 11.2 EB05 9.6 · IC025 +3.1 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.8 (1.5–2.2) | Not in label — unassessed | serious n=120 · 100% clinician | no trial arm names this drug |
| Foetal death | 290 | 11.4 10.1–12.8ROR 11.4 · calibrated p 0.021 ✓ | 10.7 EB05 9.7 · IC025 +3.2 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.8–2.3) | Not in label — unassessed | serious n=290 · ♀ 100% (drug 61%) · 90% clinician | no trial arm names this drug |
| Torsade de pointes | 431 | 11.1 10.1–12.3ROR 11.2 · calibrated p 0.022 ✓ | 10.5 EB05 9.7 · IC025 +3.2 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.1 (1.9–2.4) | Labeled adverse reaction exact term | serious PRR 7.6 · 95% clinician | no trial arm names this drug |
| Personality disorder | 135 | 10.4 8.7–12.3ROR 10.4 · calibrated p 0.029 ✓ | 9.7 EB05 8.4 · IC025 +3.0 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.6–2.3) | Not in label — unassessed | serious n=135 · ♀ 100% (drug 61%) · 100% clinician | no trial arm names this drug |
| Oculogyric crisis | 106 | 10.2 8.4–12.4ROR 10.2 · calibrated p 0.032 ✓ | 9.5 EB05 8.1 · IC025 +2.9 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.2 (1.7–2.7) | Labeled adverse reaction exact term | serious n=106 · ♀ 100% (drug 61%) · 100% clinician | no trial arm names this drug |
| Febrile bone marrow aplasia | 210 | 10.1 8.8–11.7ROR 10.2 · calibrated p 0.031 ✓ | 9.6 EB05 8.5 · IC025 +3.0 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.7–2.4) | Not in label — unassessed | serious n=210 · 100% clinician | no trial arm names this drug |
| Food allergy | 378 | 10.1 9.1–11.2ROR 10.2 · calibrated p 0.031 ✓ | 9.6 EB05 8.8 · IC025 +3.1 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.7–2.2) | Not in label — unassessed | serious n=373 · ♀ 100% (drug 61%) | no trial arm names this drug |
| Aplasia | 98 | 9.9 8.1–12.1ROR 9.9 · calibrated p 0.035 ✓ | 9.3 EB05 7.8 · IC025 +2.8 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.6–2.5) | Not in label — unassessed | serious n=98 · 100% clinician | no trial arm names this drug |
| Serotonin syndrome | 919 | 9.7 9.1–10.4ROR 9.8 · calibrated p 0.035 ✓ | 9.3 EB05 8.8 · IC025 +3.1 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.8–2.1) | Labeled adverse reaction exact term | age-adj. PRR 8.2 · serious PRR 6.7 · 92% clinician | no trial arm names this drug |
| Ventricular fibrillation | 533 | 9.7 8.9–10.5ROR 9.7 · calibrated p 0.036 ✓ | 9.2 EB05 8.6 · IC025 +3.1 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.8–2.3) | Labeled (related wording) related wording | age-adj. PRR 8.4 · serious PRR 6.6 · ♀ 34% (drug 61%) · 95% clinician | no trial arm names this drug |
| Long qt syndrome | 115 | 9.6 8.0–11.6ROR 9.6 · calibrated p 0.038 ✓ | 9.0 EB05 7.7 · IC025 +2.8 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.1 (1.7–2.6) | Labeled adverse reaction exact term | serious n=116 · ♀ 100% (drug 61%) · 100% clinician | no trial arm names this drug |
| End stage renal disease | 876 | 9.6 9.0–10.3ROR 9.7 · calibrated p 0.036 ✓ | 9.2 EB05 8.7 · IC025 +3.1 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.1 (2.0–2.3) | Not in label — unassessed | serious PRR 6.5 | no trial arm names this drug |
| Pseudomonal sepsis | 81 | 9.3 7.4–11.6ROR 9.3 · calibrated p 0.044 ✓ | 8.6 EB05 7.1 · IC025 +2.7 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.5–2.6) | Not in label — unassessed | serious n=81 · 100% clinician | no trial arm names this drug |
| Cytokine release syndrome | 858 | 9.1 8.5–9.7ROR 9.1 · calibrated p 0.044 ✓ | 8.7 EB05 8.2 · IC025 +3.0 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.8–2.1) | Not in label — unassessed | age-adj. PRR 8.6 · serious PRR 6.3 · ♀ 39% (drug 61%) · 96% clinician | no trial arm names this drug |
| Heart disease congenital | 152 | 8.5 7.3–10.0ROR 8.5 · calibrated p 0.056 | 8.1 EB05 7.0 · IC025 +2.7 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.6–2.3) | Labeled (related wording) related wording | serious n=152 | no trial arm names this drug |
| Total lung capacity decreased | 68 | 8.5 6.7–10.9ROR 8.5 · calibrated p 0.058 | 7.9 EB05 6.4 · IC025 +2.6 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.5–2.7) | Not in label — unassessed | serious n=67 · ♀ 0% (drug 61%) · 100% clinician | no trial arm names this drug |
| Clonus | 116 | 8.5 7.0–10.2ROR 8.5 · calibrated p 0.057 | 8.0 EB05 6.8 · IC025 +2.7 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.6–2.5) | Labeled adverse reaction exact term | serious n=116 · 100% clinician | no trial arm names this drug |
| Escherichia bacteraemia | 92 | 8.0 6.5–9.8ROR 8.0 · calibrated p 0.070 | 7.5 EB05 6.2 · IC025 +2.5 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 2.0 (1.6–2.6) | Not in label — unassessed | serious n=92 · 100% clinician | no trial arm names this drug |
Clinical concept groups
MedDRA splits one clinical problem across several terms (e.g. "neutropenia", "neutrophil count decreased", "agranulocytosis"), which dilutes term-level signals. These rows count reports with any term in a concept group (an exact union, not a sum), compared with all other drugs. Groups are hand-built and listed in the methods.
| Concept | Reports | PRR 95% CI | Reading |
|---|---|---|---|
| Neutropenia / agranulocytosis | 7,777 | 6.26.1–6.4 | signal |
| Hyponatraemia | 1,567 | 3.83.6–4.0 | signal |
| Thrombocytopenia | 4,067 | 3.63.5–3.7 | signal |
| Anaemia | 4,591 | 3.02.9–3.1 | signal |
| Arrhythmia / qt | 2,872 | 2.92.8–3.0 | signal |
| Kidney injury | 6,181 | 2.62.6–2.7 | signal |
| Serious infection | 9,392 | 2.42.3–2.4 | signal |
| Anaphylaxis / angioedema | 1,485 | 2.32.2–2.4 | signal |
| Pancreatitis | 836 | 2.01.9–2.2 | raised |
| Venous thromboembolism | 2,228 | 2.01.9–2.1 | raised |
| Liver injury | 2,922 | 1.91.8–1.9 | raised |
| Severe cutaneous reaction | 597 | 1.61.4–1.7 | raised |
| Extrapyramidal | 789 | 1.41.4–1.6 | raised |
| Interstitial lung disease | 717 | 1.41.3–1.6 | raised |
| Gi bleeding | 1,349 | 1.41.4–1.5 | raised |
| Seizure | 1,395 | 1.41.3–1.4 | raised |
Trial evidence (ClinicalTrials.gov)
ClinicalTrials.gov returned results-bearing trials mentioning Ondansetron only as a background or rescue medication (NCT02625181, NCT00619359); no trial listing it as the tested intervention was cached, so no trial cross-check is shown.
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 |
|---|---|---|---|---|---|---|
| Nausea | 12,309 | 3.0 3.0–3.1ROR 3.3 · calibrated p 0.535 | 3.0 EB05 3.0 · IC025 +1.6 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.8 (1.8–1.9) | Likely indication confounding term in indications; also in warnings | age-adj. PRR 2.7 · serious PRR 3.0 | no trial arm names this drug |
| Fatigue (tiredness) | 8,932 | 2.2 2.2–2.3ROR 2.3 · calibrated p 0.882 | 2.2 EB05 2.2 · IC025 +1.1 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.9–2.0) | Labeled adverse reaction exact term | age-adj. PRR 1.9 · serious PRR 2.1 | no trial arm names this drug |
| Diarrhoea (diarrhea) | 8,296 | 2.5 2.5–2.6ROR 2.6 · calibrated p 0.758 | 2.5 EB05 2.4 · IC025 +1.3 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.8–1.9) | Labeled adverse reaction exact term | age-adj. PRR 2.2 · serious PRR 2.3 | no trial arm names this drug |
| Vomiting | 7,706 | 3.2 3.1–3.3ROR 3.4 · calibrated p 0.516 | 3.2 EB05 3.1 · IC025 +1.6 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.8–1.9) | Likely indication confounding term in indications; also in warnings | age-adj. PRR 2.8 · serious PRR 2.8 | no trial arm names this drug |
| Off label use (used outside approved label) | 6,936 | 1.5 1.5–1.6ROR 1.6 · calibrated p 0.696 | 1.5 EB05 1.5 · IC025 +0.6 vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.9–1.9) | Reporting / coding artifact | age-adj. PRR 1.4 · serious PRR 1.6 | no trial arm names this drug |
| Death | 5,109 | 1.1 1.1–1.2ROR 1.2 · calibrated p 0.408 | 1.1 EB05 1.1 · IC025 +0.1 vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.8–2.0) | Outcome field, not a reaction | age-adj. PRR 1.2 · serious PRR 0.8 | no trial arm names this drug |
| Dyspnoea (shortness of breath) | 4,998 | 1.7 1.7–1.8ROR 1.7 · calibrated p 0.798 | 1.7 EB05 1.7 · IC025 +0.7 vs other Serotonin-3 Receptor Antagonists: PRR 1.8 (1.7–1.8) | Labeled (related wording) related wording | age-adj. PRR 1.6 · serious PRR 1.5 | no trial arm names this drug |
| Pyrexia (fever) | 4,992 | 2.8 2.7–2.9ROR 2.9 · calibrated p 0.661 | 2.8 EB05 2.7 · IC025 +1.4 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.8 (1.8–1.9) | Labeled adverse reaction exact term | age-adj. PRR 2.4 · serious PRR 2.3 | no trial arm names this drug |
| Febrile neutropenia | 4,690 | 14.6 14.2–15.1ROR 15.3 · calibrated p 0.006 ✓ | 13.7 EB05 13.3 · IC025 +3.7 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.8 (1.8–1.9) | Not in label — unassessed | age-adj. PRR 13.5 · serious PRR 9.8 · 95% clinician | no trial arm names this drug |
| Pain | 4,628 | 1.5 1.4–1.5ROR 1.5 · calibrated p 0.625 | 1.5 EB05 1.4 · IC025 +0.5 vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.9–2.0) | Not in label — unassessed | age-adj. PRR 1.5 · serious PRR 1.3 | no trial arm names this drug |
| Headache | 4,477 | 1.4 1.3–1.4ROR 1.4 · calibrated p 0.575 | 1.4 EB05 1.3 · IC025 +0.4 vs other Serotonin-3 Receptor Antagonists: PRR 1.8 (1.8–1.9) | Labeled adverse reaction exact term | age-adj. PRR 1.2 · serious PRR 1.5 | no trial arm names this drug |
| Constipation | 4,162 | 3.8 3.7–3.9ROR 3.9 · calibrated p 0.401 | 3.7 EB05 3.6 · IC025 +1.8 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.8–1.9) | Labeled adverse reaction exact term | age-adj. PRR 3.5 · serious PRR 3.7 | no trial arm names this drug |
| Asthenia (weakness) | 3,890 | 2.0 1.9–2.1ROR 2.0 · calibrated p 0.968 | 2.0 EB05 1.9 · IC025 +0.9 vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.8–1.9) | Not in label — unassessed | age-adj. PRR 1.7 · serious PRR 1.7 | no trial arm names this drug |
| Drug ineffective (drug did not work) | 3,846 | 0.6 0.5–0.6ROR 0.5 · calibrated p 0.064 | 0.6 EB05 0.5 · IC025 -0.9 PRR-only: not supported by EBGM or IC vs other Serotonin-3 Receptor Antagonists: PRR 1.9 (1.8–2.0) | Reporting / coding artifact | age-adj. PRR 0.6 · serious PRR 0.8 | no trial arm names this drug |
| Pneumonia (lung infection) | 3,638 | 2.2 2.1–2.3ROR 2.2 · calibrated p 0.938 | 2.2 EB05 2.1 · IC025 +1.1 3/3 methods agree vs other Serotonin-3 Receptor Antagonists: PRR 1.8 (1.8–1.9) | Not in label — unassessed | age-adj. PRR 2.0 · serious PRR 1.6 | no trial arm names this drug |
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.
- Appendicolith — n=266, PRR 462.4
- Neurologic neglect syndrome — n=130, PRR 58.2
- Left-to-right cardiac shunt — n=68, PRR 57.3
- Carotid artery thrombosis — n=138, PRR 37.1
- Chronic kidney disease-mineral and bone disorder — n=139, PRR 28.5
- Temperature regulation disorder — n=244, PRR 24.2
- Adjustment disorder — n=136, PRR 22.4
- Aplastic anaemia — n=534, PRR 21.8
- Nephrogenic anaemia — n=451, PRR 20.5
- Hyperparathyroidism secondary — n=220, PRR 18.3
✓ A hand-written Bradford Hill causality assessment exists for this drug: Ondansetron (5-HT3 antagonists) ↔ QT prolongation / torsades.
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 Ondansetron?
In FDA FAERS, the most frequently co-reported reaction terms for Ondansetron are nausea, fatigue, diarrhoea, vomiting, dyspnoea, pyrexia. 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 Ondansetron have an FDA boxed warning?
No. The FDA label retrieved for Ondansetron has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Ondansetron 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 10afd68b-877f-4819-a314-39f2d56d5db9, effective 20250915; matched on
openfda.generic_name.exact:"ONDANSETRON" AND openfda.product_type:"HUMAN PRESCRIPTION DRUG") - PubChem CID 4595 description (ChEBI)
- 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, 1,203 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
ONDANSETRON, 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.