← All causality assessments
Contested: signal not confirmed by large randomized trials
Causality assessment · Contested: signal not confirmed by large randomized trials
Isotretinoin and Inflammatory bowel disease: 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.
Isotretinoin ↔ Inflammatory bowel disease
n=5,252 co-reports · PRR 494.6 · ROR 553.6
Isotretinoin has been linked to inflammatory bowel disease in case reports and some observational studies, but large cohort and meta-analytic analyses have not confirmed a causal increase; 5,252 co-reports nevertheless give PRR 494.6, a signal inflated by channeling and confounding. It is graded contested rather than established.
Regulatory basis: literature — isotretinoin and inflammatory bowel disease; label lists IBD among reported events but the association is disputed.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Courses over months |
| Strength | met | PRR 494.6, inflated by channeling |
| Consistency | partial | Observational studies disagree |
| Specificity | not established | Acne populations differ |
| Biological gradient | not established | No clear dose relation |
| Plausibility | partial | Mechanism proposed but unproven |
| Coherence | partial | Cohort data argue against causality |
| Experiment | n/a | Large cohorts did not confirm |
| Analogy | partial | Contrasted with other acne therapies |
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 isotretinoin captured inflammatory bowel disease as a tracked adverse event in a usable structure. Observational designs are confounded by indication; meta-analyses of cohorts did not confirm the association.