LFT Monitoring for Pirfenidone
Perform liver function tests (ALT, AST, and bilirubin) at baseline, monthly for the first 6 months, then every 3 months thereafter. 1, 2, 3
Baseline Testing
- Obtain ALT, AST, and bilirubin levels prior to initiating pirfenidone therapy 3
- This baseline assessment is mandatory before starting treatment 1, 2
Monitoring Schedule
First 6 Months
- Monthly LFT monitoring (ALT, AST, bilirubin) 1, 2, 3
- This intensive early monitoring period captures the majority of hepatotoxic events, which typically occur within the first 6 months of therapy 3
After 6 Months
- Every 3 months for the duration of treatment 1, 2, 3
- Continue this schedule indefinitely while on pirfenidone 1
Additional Monitoring Triggers
- Promptly measure LFTs if patients report symptoms suggesting liver injury: fatigue, anorexia, right upper abdominal discomfort, dark urine, or jaundice 3
- These symptoms warrant immediate testing regardless of the scheduled monitoring interval 3
Management of Elevated Liver Enzymes
ALT/AST >3× but ≤5× ULN (without symptoms or hyperbilirubinemia)
- Discontinue confounding medications and exclude other causes 3
- Monitor closely with repeat testing as clinically indicated 3
- May maintain full dose if clinically appropriate, or reduce/interrupt dosing until normalization 3
ALT/AST >3× but ≤5× ULN (with symptoms or hyperbilirubinemia)
ALT/AST >5× ULN
Clinical Context
The monitoring schedule is critical because drug-induced liver injury (DILI) with pirfenidone, while uncommon (3.7% with elevations ≥3× ULN in phase 3 trials), can progress to acute liver failure with fatal outcomes in rare cases 3, 4. Elevations are generally reversible with dose modification or discontinuation when detected early 3, 5. The monthly monitoring during the first 6 months captures the period of highest risk, as most photosensitivity and other adverse events occur during this initial treatment phase 3.