Pharmacokinetics in liver disease and critical illness
Hepatic extraction ratio and why cirrhosis raises oral bioavailability of high-extraction drugs, choosing drugs in liver disease, and how capillary leak, hypoalbuminaemia and augmented renal clearance change antibiotic dosing in sepsis.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Hepatic clearance = Q (liver blood flow) × E (extraction ratio).
- High-extraction drugs (E over 0.7) are cleared as fast as blood brings them, so their clearance follows blood flow. Oral doses lose most of the drug to first-pass metabolism.
- Low-extraction drugs (E under 0.3) depend on enzyme capacity and the unbound fraction.
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Sources
- Australian Medicines HandbookAU/NZAustralian Medicines Handbook Pty Ltd, 2026
- Therapeutic Guidelines: Prescribing in special populations (hepatic impairment); AntibioticAU/NZTherapeutic Guidelines Ltd, 2026
- Pharmacokinetics and dosage adjustment in patients with hepatic dysfunctionEuropean Journal of Clinical Pharmacology (Verbeeck, 2008;64:1147-61), 2008
- Individualised antibiotic dosing for patients who are critically ill: challenges and potential solutionsLancet Infectious Diseases (Roberts et al., 2014;14:498-509), 2014
- Continuous vs intermittent beta-lactam antibiotic infusions in critically ill patients with sepsis: the BLING III randomized clinical trialJAMA (Dulhunty et al., 2024;332:629-37), 2024
- Last updated
- 14 November 2026
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