What effect does hepatic impairment typically have on hepatic clearance?

• A. Reduces clearance by lowering metabolism.
• B. Increases clearance.
• C. No effect on hepatic clearance.
• D. Only renal clearance matters.

Answer: (A)

Hepatic clearance reflects the liver’s ability to metabolize and excrete drugs, so when liver function is impaired, its metabolic capacity declines. This means intrinsic clearance (the liver’s enzymatic ability to metabolize the drug) drops, and that reduction usually lowers overall hepatic clearance. For drugs with low extraction ratios, hepatic clearance is roughly proportional to fu × Clint, so a decrease in Clint from impaired enzyme activity directly reduces clearance, even if the unbound fraction fu changes a bit due to altered protein binding. In practice, hepatic impairment often leads to longer half-lives and greater exposure because the liver can’t metabolize as efficiently. Therefore, hepatic impairment typically reduces hepatic clearance by lowering metabolism.