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Causality: well established
Causality assessment · Causality: well established
Valproate 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.
Valproate ↔ Thrombocytopenia
n=455 co-reports · PRR 4.2 · ROR 4.2
Valproate commonly lowers platelet counts through dose-related marrow suppression and can impair platelet function; 455 co-reports give PRR 4.2. Blood counts are checked before surgery and in patients with bruising or bleeding.
Regulatory basis: valproate prescribing information — thrombocytopenia; blood-count monitoring.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Gradual, dose-related |
| Strength | met | PRR 4.2 with 455 co-reports |
| Consistency | met | Consistent across cohorts |
| Specificity | not established | Low platelets are common |
| Biological gradient | met | Dose-related |
| Plausibility | met | Plausible marrow suppression |
| Coherence | met | Fits valproate haematological effects |
| Experiment | n/a | Rarely coded as a trial endpoint |
| Analogy | met | Analogous to other drug-induced 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 valproate captured thrombocytopenia as a tracked adverse event in a usable structure. Trials did not routinely report platelet counts as coded adverse events.