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Causality: well established
Causality assessment · Causality: well established
Ondansetron and Prolonged QT interval: is the FAERS signal real?
A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.
Ondansetron ↔ Prolonged QT interval
n=1,167 co-reports · PRR 6.4 · ROR 6.5
Ondansetron, a 5-HT3 antagonist used for nausea and vomiting, prolongs the QT interval dose-dependently and can rarely trigger torsades de pointes; 1,167 co-reports give PRR 6.4. The label advises caution with electrolyte disturbance or other QT-prolonging drugs and limits single intravenous doses.
Regulatory basis: ondansetron prescribing information — QT-prolongation warning; dose limits and ECG caution.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Within minutes to hours |
| Strength | met | PRR 6.4 with 1,167 co-reports |
| Consistency | met | Reproduced in QT studies |
| Specificity | not established | QT prolongation is common |
| Biological gradient | met | Dose-related |
| Plausibility | met | Known cardiac ion-channel effect |
| Coherence | met | Fits ondansetron's cardiac effect |
| Experiment | n/a | Measured in dedicated QT trials |
| Analogy | met | Analogous to other QT-prolonging antiemetics |
This table is this page's own qualitative read of the literature cited above, not an automated or citation-gated assessment — see the note at the bottom of this page.
✗ No ClinicalTrials.gov results-posting trial in the top search hits for ondansetron captured prolonged qt interval as a tracked adverse event in a usable structure. Transient QT changes are usually protocol-monitored rather than coded as an adverse event.