Tigecycline and Elevated Liver Enzymes
Tigecycline, an intravenous glycylcycline antibiotic for complicated infections, commonly causes elevated liver enzymes as a side effect. Clinical trials and post-marketing data show transaminase elevations (ALT/AST) in 15-30% of patients, depending on dose and duration.[1][2]
Frequency from Key Clinical Trials
In phase 3 trials for skin/skin structure infections and intra-abdominal infections:
- ALT elevations (>3x upper limit of normal, ULN): 13-26%.
- AST elevations (>3x ULN): 12-20%.
- Severe cases (>10x ULN): 1-2%.[1][3]
Hospital-acquired pneumonia trials reported similar rates, up to 25% for ALT.[2] These occurred mostly within the first week, resolving after discontinuation in most cases.
Risk Factors and Severity
Higher doses (100 mg loading, 50 mg BID maintenance) increase incidence to 25-30% vs. 15-20% at standard 50 mg BID.[4] Pre-existing liver disease or concurrent hepatotoxins raise risk. Most elevations are mild-moderate (3-5x ULN) and asymptomatic; hepatic failure is rare (<0.5%).[1][5]
What Happens If Levels Rise?
Monitor LFTs weekly during therapy (up to 14 days). Hold or discontinue if >5x ULN with symptoms or >10x ULN.[2] Resolution typically occurs within 1-4 weeks post-treatment. No specific antidote; supportive care only.[3]
Comparison to Other Antibiotics
Tigecycline elevates enzymes more often than comparators:
| Drug | ALT >3x ULN Rate |
|------|------------------|
| Tigecycline | 15-26% [1] |
| Imipenem | 1-3% [3] |
| Vancomycin | 2-5% [6] |
| Levofloxacin | 4-8% [6] |
This limits its use in patients with liver concerns.
Regulatory Warnings and Monitoring Guidelines
FDA label lists 'abnormal liver function tests' in 25% of patients, with black box for mortality risk (not liver-specific).[2] EMA notes similar rates, advising LFT checks at baseline, days 3-4, and weekly.[5] Avoid in severe hepatic impairment (Child-Pugh C).
[1]: Tigecycline Prescribing Information (Pfizer)
[2]: FDA Tygacil Label
[3]: Taiwo et al., Clin Infect Dis 2006;42(Suppl 4):S258-64
[4]: Muralidharan et al., Antimicrob Agents Chemother 2005;49:220-9
[5]: EMA Tygacil EPAR
[6]: Owens et al., Diagn Microbiol Infect Dis 2008;61:235-42