Acetaminophen hepatotoxicity: NO to the rescue.

Severe liver injury as a result of overdose or chronic use of acetaminophen (paracetamol) remains a significant clinical problem, accounting for as much as 40% of cases of acute liver failure. The mechanisms underlying the liver injury caused by acetaminophen have become much better understood in recent years. In this issue, Fiorucci et al. report that delivery of nitric oxide (NO) in small amounts to the liver, via a novel derivative of the bile acid ursodeoxycholic acid, results in significant protection of the liver from acetaminophen-induced damage. NO appears to produce these beneficial actions through several mechanisms, including the suppression of synthesis of several proinflammatory cytokines. There is also substantial evidence that a NO-releasing derivative of acetaminophen offers several advantages over acetaminophen itself, including enhanced analgesic potency and reduced liver toxicity.