Clinically apparent liver injury from NSAIDs is rare (~1-10 cases per 100,000 prescriptions) and typically presents as acute hepatitis within 1 to 3 months of starting the medication. However, use of NSAIDs, even for a short period of time, can harm the kidneys. NSAIDs cause unopposed constriction of the afferent arteriole and decrease renal perfusion pressure.
Acetaminophen (brand names Panadol, Tylenol) overdose, in contrast, can cause a serious acute liver injury and hepatic failure that can result in death or need for emergency liver transplantation. Currently, acetaminophen is the major cause of acute liver failure in the United States, Europe and Australia.