Management of Elevated ALT Levels

Initial Assessment and Monitoring

For patients with normal baseline ALT (<1.5× ULN), investigate when ALT reaches ≥3× ULN; for those with elevated baseline (≥1.5× ULN), investigate when ALT reaches ≥2× baseline, and always stop potentially hepatotoxic drugs when ALT ≥5× ULN or when accompanied by bilirubin ≥2× ULN 1, 2, 3
Normal baseline ALT (<1.5× ULN): Stop drug if ALT ≥5× ULN alone, or if ALT ≥3× ULN plus bilirubin ≥2× ULN or hepatic symptoms 1
Elevated baseline ALT (≥1.5× ULN): Stop drug if ALT ≥3× baseline or ≥300 U/L (whichever comes first), or if ALT ≥2× baseline plus bilirubin ≥2× ULN 1

For women, using upper reference limit of 25 IU/L, ALT >125 IU/L (5× ULN) is particularly concerning and rarely attributable to NAFLD alone 4
Near-normal baseline (<1.5× ULN): Withhold study drug at ALT >5× ULN without bilirubin elevation, or at ALT >3× ULN with bilirubin ≥2× ULN 3
Baseline ALT 1.5-3× ULN: Withhold at ALT >6× ULN 3
Baseline ALT 3-5× ULN: Withhold at ALT >8× ULN 3

If ALT <2× ULN at baseline: Repeat at 2 weeks; if still <2× ULN, monitor only for symptoms 7
If ALT 2-5× ULN: Monitor weekly for 2 weeks, then biweekly until normal 7
If ALT ≥5× ULN or bilirubin rises: Stop rifampicin, isoniazid, and pyrazinamide immediately 7
Normal baseline ALT (<1.5× ULN): Evaluate for immune-mediated liver injury when ALT ≥3× ULN 2
Elevated baseline ALT (≥1.5× ULN): Evaluate when ALT ≥2× baseline 2
If no response to corticosteroids within 4-6 weeks: Repeat evaluation and consider liver biopsy 2