Source data
The register is built from the
openFDA FAERS endpoint
using the API's server-side ?count= aggregation. FAERS
(FDA Adverse Event Reporting System) is the FDA's canonical post-market
surveillance database for drug adverse events and contains over 20
million reports. Branmoor does not pull raw reports for v1 — the
aggregated counts are sufficient and far more efficient.
What v1 reports
- Top 500 drugs by total FAERS report volume in 2025
- Serious-event count per drug (reports flagged as resulting in death, life-threatening event, hospitalization, disability, congenital anomaly, or other medically important condition)
- Fatal-outcome count per drug (reports specifically flagged as resulting in death)
- Fatality share — the ratio of fatal reports to serious reports; a navigation aid, not a clinical mortality rate
- Top 10 reactions per drug among serious-only reports, using MedDRA Preferred Terms (only for top 247 drugs by volume)
What FAERS is — and isn't
FAERS is a passive, voluntary reporting system. Reports are submitted by pharmaceutical manufacturers (mandatory), healthcare professionals (voluntary), and consumers (voluntary). A FAERS report does not mean the drug caused the event; it means someone reported an association. FAERS counts are heavily confounded by:
- Reporting rates — established manufacturers with mature pharmacovigilance infrastructure file more reports than smaller manufacturers selling identical generics
- Population sickness — specialty biologics for serious disease (e.g., rheumatoid arthritis, oncology) will always show more serious events than over-the-counter agents because the underlying patients are sicker
- Stimulated reporting — media coverage, litigation, and labeling changes drive temporary spikes in reporting that don't reflect underlying incidence
- Polypharmacy — many reports list multiple drugs; FAERS counts each drug, so a single event with 5 drugs increments 5 counts
- Indication channeling — drugs prescribed for terminal conditions will have higher fatality shares regardless of drug-specific risk
The fatal-share column is a navigation aid, not a clinical assertion. A drug with a 50% fatal share among serious reports is generally a drug prescribed to terminally ill patients, not a drug that kills half its users.
What the paid Signal Surveillance layer adds
The full FAERS Interaction Surveillance product is a pharmacovigilance signal-detection system. It normalizes the confounders above and surfaces emerging signal against the FAERS baseline. The v2 layer adds:
- Information Component (IC) — the canonical Bayesian disproportionality measure, normalizes for differential reporting rates
- Empirical Bayes Geometric Mean (EBGM) — the FDA's preferred frequentist metric, with confidence bounds
- Proportional Reporting Ratio (PRR) with chi-squared significance — the legacy methodology, useful for cross-reference
- Drug-drug interaction signal — disproportionality of (Drug A + Drug B + Reaction X) co-occurrence vs. (each drug + Reaction X) separately
- Comparison against the FDA SPL labeling — new-signal flagging when a disproportionality signal emerges for a reaction not currently in the drug's labeled adverse-event profile
- Polypharmacy patterns — particularly in elderly and renally-impaired populations, cross-referenced with Medicare Part D Public Use Files
See the product page for the v2 layer and the pharma pharmacovigilance / PBM clinical ops / malpractice-carrier sales motion.
Update cadence
openFDA refreshes FAERS quarterly as FDA publishes new release notes. Branmoor re-ingests on each site deploy.