R Factor for Drug-Induced Liver Injury (DILI)
Classifies drug-induced liver injury (DILI) as hepatocellular, cholestatic, or mixed based on the pattern of liver enzyme elevation. Used in CIOMS/RUCAM assessment.
Score interpretation
R <2 — Cholestatic DILI pattern. Predominantly ALP elevation.
→ Suspect bile duct injury; investigate with imaging (MRCP); suspect drugs: antibiotics (amoxicillin-clavulanate), antifungals, steroids
R 2–5 — Mixed hepatocellular/cholestatic DILI pattern.
→ Both hepatocellular and cholestatic features; full RUCAM/CIOMS assessment; consider liver biopsy if diagnosis unclear
R ≥5 — Hepatocellular DILI pattern. Predominantly ALT elevation.
→ Higher risk of acute liver failure; monitor closely; stop offending drug immediately; suspect drugs: NSAIDs, antibiotics, antiepileptics, herbal products
Interpretation bands for the R Factor. Apply clinical judgement and local guidance.
References
- Danan G, Benichou C. Causality assessment of adverse reactions to drugs. J Clin Epidemiol. 1993;46(11):1323–1330.
Related
Curated clinical cross-links plus same-class fallbacks.
- Sulfasalazine · Aminosalicylate / Disease-Modifying Antirheumatic Drug (DMARD)
- Factor IX (Specialist drug) · Recombinant clotting factor IX
- Factor VIII (Specialist drug) · Recombinant clotting factor VIII
- Factor VIII inhibitor bypassing fraction (Specialist drug) · Activated prothrombin complex concentrate
- Factor XIII (Specialist drug) · Plasma-derived factor XIII concentrate
- Factor XIII A-subunit (Specialist drug) · Recombinant factor XIII A-subunit
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.