Naproxen-induced liver injury is very rare (1-3 cases per 100,000 exposed individuals), typically occurring 1-6 weeks after ingestion¹. 2011 BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) have been reported to induce liver injury. Patterns of the injury usually range from mild … Metabolism: Naproxen is extensively metabolized in the liver by cytochrome P450 to 6-0-desmethyl naproxen. Elimination: Metabolites excreted in the urine …