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Causality: well established
Causality assessment · Causality: well established
Quinine and Thrombocytopenia: 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.
Quinine ↔ Thrombocytopenia
n=172 co-reports · PRR 3.8 · ROR 3.9
Quinine is an antimalarial and muscle-cramp remedy; it can trigger immune thrombocytopenia through drug-dependent platelet antibodies, appearing here as 172 co-reports (PRR 3.8). The reaction can be severe and recur rapidly on re-exposure, so the label warns of thrombocytopenia and advises stopping the drug if it occurs.
Regulatory basis: quinine prescribing information — immune thrombocytopenia warning.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Platelet fall within days of exposure |
| Strength | met | PRR 3.8, modest |
| Consistency | met | Reproduced across case series |
| Specificity | met | Highly specific to quinine |
| Biological gradient | not established | Not dose-related (immune) |
| Plausibility | met | Drug-dependent platelet antibodies |
| Coherence | met | Fits the mechanism |
| Experiment | n/a | Too rare for trial detection |
| Analogy | met | Analogous to other drug-induced immune thrombocytopenia |
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 quinine captured thrombocytopenia as a tracked adverse event in a usable structure. Quinine-induced thrombocytopenia is rare and idiosyncratic, so malaria and cramp trials did not capture it as a coded event.