Does Bilirubin Increase with Methotrexate or Steroids?
Yes, methotrexate can cause bilirubin elevation as part of its hepatotoxic effects, while steroids do not typically cause hyperbilirubinemia and may even be associated with increased bilirubin in specific contexts unrelated to direct hepatotoxicity.
Methotrexate and Bilirubin
Methotrexate is well-established as a hepatotoxic agent that requires monitoring of liver function tests, including bilirubin. Before initiating methotrexate therapy, baseline laboratory tests including albumin and bilirubin should be obtained 1. This monitoring requirement exists precisely because methotrexate can affect bilirubin levels.
Frequency and Clinical Significance
The hepatotoxicity profile varies by dose and clinical context:
Low-dose methotrexate (used for psoriasis, rheumatoid arthritis): Transient liver function test abnormalities occur frequently and are usually not cause for modification of therapy 2. Persistent abnormalities in liver function tests and/or depression of serum albumin may indicate serious liver toxicity 2.
High-dose methotrexate: Hyperbilirubinemia occurs in approximately 25% of courses, typically grade ≤2, and is generally transient and reversible 3. However, severe grade 4 hyperbilirubinemia, while extremely rare, has been documented and is reversible 3.
In specific populations: When busulfan/cyclophosphamide conditioning is combined with methotrexate for GVHD prophylaxis, hyperbilirubinemia (bilirubin ≥2 mg/dL) increased from 48% to 80%, with mean maximal bilirubin rising from 4.67 to 8.72 mg/dL 4.
Monitoring Requirements
Liver chemistries including alkaline phosphatase and serum albumin levels should be performed every 4 weeks initially, with more frequent monitoring when hepatic risk factors are present 1. For patients on stable doses without risk factors, monitoring can be extended to every 1-3 months 5.
Methotrexate should be stopped if there is a confirmed increase in ALT/AST greater than three times the upper limit of normal, but may be reinstituted at a lower dose following normalization 5. While this recommendation focuses on transaminases, persistent elevation of bilirubin alongside other liver function abnormalities warrants evaluation and potential discontinuation.
Important Caveats
Analytical interference: At very high methotrexate concentrations (>1000 μmol/L), methotrexate can artificially elevate measured conjugated bilirubin on certain analyzers (Kodak Ektachem 400), making apparent conjugated bilirubin exceed total bilirubin 6. This is a laboratory artifact, not true hyperbilirubinemia.
Risk factors for hepatotoxicity that may predispose to bilirubin elevation include: obesity (BMI ≥40), diabetes, hyperlipidemia, greater than moderate alcohol use, chronic liver disease (hepatitis B/C), and concomitant hepatotoxic drugs 7, 1.
Steroids and Bilirubin
Corticosteroids do not typically cause direct hepatotoxicity or hyperbilirubinemia. The evidence provided does not support steroids as a cause of elevated bilirubin through hepatotoxic mechanisms.
One case report 8 described a TTP patient whose bilirubin paradoxically increased during methylprednisolone treatment and normalized within 4 days after steroid discontinuation. However, this occurred in the context of severe ADAMTS-13 deficiency and TTP, where the bilirubin elevation was likely related to ongoing hemolysis rather than steroid-induced hepatotoxicity. This represents an isolated observation in a complex clinical scenario, not a generalizable pattern.
Pediatric Considerations
When interpreting methotrexate hepatotoxicity data in children, note that many published studies involve rheumatology patients treated with concomitant oral corticosteroids 1. The presence of steroids in these regimens did not appear to contribute to hepatotoxicity; rather, the primary concern remained methotrexate-related liver effects.
Clinical Algorithm
For patients starting methotrexate:
- Obtain baseline bilirubin, albumin, ALT, AST, alkaline phosphatase 1
- Screen for hepatotoxicity risk factors (alcohol, obesity, diabetes, viral hepatitis)
- Monitor liver function tests monthly for first 6 months, then every 1-3 months 1
- If bilirubin rises alongside transaminase elevation >3× ULN: stop methotrexate, investigate other causes, may restart at lower dose after normalization 5
- Consider non-invasive liver fibrosis assessment (FIB-4 index, transient elastography) in patients with persistent abnormalities or risk factors 7
For patients on steroids: Routine bilirubin monitoring is not required based on steroid use alone, as steroids do not cause direct hepatotoxicity leading to hyperbilirubinemia.