Tigecycline Clearance Basics
Tigecycline, a glycylcycline antibiotic, undergoes minimal renal clearance (about 15-20% unchanged). Its primary elimination route is biliary/fecal excretion (around 60%), driven by hepatic metabolism and transport via bile.[1]
Impact of Mild Hepatic Impairment (Child-Pugh A)
Clearance decreases by approximately 25-30%. AUC increases by 22-40%, but steady-state exposure remains similar to healthy patients due to adjusted dosing. No dose adjustment needed.[1][2]
Impact of Moderate Hepatic Impairment (Child-Pugh B)
Clearance drops by 40-55%. AUC rises 60-90%, prolonging half-life to 30-40 hours. Reduce maintenance dose to 25 mg IV every 12 hours after 100 mg loading dose.[1][2]
Impact of Severe Hepatic Impairment (Child-Pugh C)
Clearance reduced by 65% or more. AUC increases over 200%, with half-life exceeding 50 hours. Tigecycline use is not recommended due to limited data and high exposure risk.[1][2]
Clinical Dosing Adjustments
| Hepatic Status | Loading Dose | Maintenance Dose | Notes |
|---------------|--------------|------------------|-------|
| Normal/Mild (A) | 100 mg | 50 mg q12h | Standard |
| Moderate (B) | 100 mg | 25 mg q12h | Monitor closely |
| Severe (C) | Avoid | Avoid | Insufficient safety data |
Adjustments based on PK studies in 56 patients with cirrhosis.[2]
Why Hepatic Impairment Slows Clearance
Tigecycline relies on hepatic uptake (OATP1B1), glucuronidation (minimal), and biliary efflux (P-gp, BCRP). Cirrhosis impairs transporter function and portal blood flow, reducing clearance without active metabolites accumulating.[1][3]
Patient Monitoring and Risks
Monitor for prolonged exposure effects like nausea, elevated liver enzymes, or superinfections. No renal adjustment needed, even in combo impairment. Avoid in end-stage liver disease.[1]
Sources
[1]: Tigecycline Prescribing Information (Pfizer)
[2]: Mueller et al., Clin Pharmacokinet 2009; tigecycline PK in hepatic impairment
[3]: FDA Clinical Pharmacology Review