Hydralazine and Drug-induced lupus: is the FAERS signal real?
Hydralazine ↔ Drug-induced lupus
Hydralazine is the archetypal cause of drug-induced lupus erythematosus — arthralgia, myalgia, fever, and serositis with anti-histone antibodies, almost never involving the kidney. It is a genuine drug effect rather than unmasked idiopathic lupus, is related to dose and duration, is commoner in slow acetylators, and typically resolves after withdrawal. The 52 FAERS co-reports (PRR 11.8) are modest because the syndrome is uncommon and often managed without being reported, but the drug–event link is among the best established in drug-induced autoimmunity.
Regulatory basis: hydralazine prescribing information (drug-induced lupus warning); the classic anti-histone drug-induced-lupus literature.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Lupus features appear after weeks–months of hydralazine and remit after withdrawal |
| Strength | partial | PRR 12, but on a small co-report count — a modest statistical signal for a well-known effect |
| Consistency | met | Reproduced across decades of case series and reviews of drug-induced lupus |
| Specificity | met | A distinctive anti-histone-antibody syndrome, unlike idiopathic SLE |
| Biological gradient | met | Dose- and duration-related, and commoner in slow acetylators |
| Plausibility | met | Hydralazine's reactive metabolites are thought to trigger the anti-histone response |
| Coherence | met | Coheres with the routine practice of stopping the drug and watching symptoms resolve |
| Experiment | partial | Dechallenge (withdrawal) is the classic confirmatory test; no randomized trial |
| Analogy | met | Analogous to procainamide- and minocycline-induced lupus |
This page's own qualitative read, not an automated/citation-gated assessment.