(p. 930) The effect of acute hepatic failure on drug handling in the critically ill 

Impaired hepatic function is a common event in intensive care unit patients and as the liver plays a central role in drug metabolism and excretion this may lead to profound changes in pharmacokinetics. Underlying mechanisms are altered enzyme function of phase I and phase II metabolism, altered transporter protein function together with cholestasis and hepatic perfusion disorders. Moreover, multidrug therapy may lead to induction and inhibition of these enzymes and transporter proteins. In addition, changes in plasma protein binding and volumes of distribution of drugs are common. Altogether, these changes may not only lead to sometimes unpredictable plasma levels of xenobiotics, but also to drug-induced liver injury when hepatocellular accumulation of noxious substances occurs. Concomitant renal dysfunction may further complicate this situation. Pharmacodynamic alterations might also occur. In conclusion, the clinician must carefully evaluate medication given to patients with hepatic failure. Therapeutic drug monitoring should be performed wherever available to guide therapy.