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Expected pharmacological effect
Causality assessment · Expected pharmacological effect
Topiramate and Nephrolithiasis: 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.
Topiramate ↔ Nephrolithiasis
n=1,504 co-reports · PRR 7.7 · ROR 7.8
Topiramate inhibits carbonic anhydrase, raising urinary pH and lowering citrate, which promotes calcium-phosphate kidney stones; 1,504 co-reports give PRR 7.7. Risk rises with long-term use, and the label advises adequate fluid intake to reduce stone formation.
Regulatory basis: topiramate prescribing information — kidney stones; increased fluid intake advised.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Months of therapy |
| Strength | met | PRR 7.7 with 1,504 co-reports |
| Consistency | met | Consistent across cohorts |
| Specificity | not established | Kidney stones are common |
| Biological gradient | met | Duration-related |
| Plausibility | met | Known carbonic-anhydrase inhibition |
| Coherence | met | Fits topiramate's renal effect |
| Experiment | n/a | Often monitored in trials |
| Analogy | met | Analogous to zonisamide and acetazolamide stones |
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 topiramate captured nephrolithiasis as a tracked adverse event in a usable structure. Kidney stones form over months and are rarely captured in epilepsy or migraine trials.