Drug-induced jaundice.

A large number of drugs may be associated with impaired bile flow. Drug-associated cholestasis presents like other forms of cholestasis with pale stools, dark urine, pruritus and jaundice. Abdominal pain may be present in some instances and can be so severe as to lead to a false diagnosis of acute cholecystitis. Biochemically, drug-associated cholestasis resembles other forms of cholestasis although the presence of eosinophilia may suggest drug involvement. Many types of drug-induced cholestasis run a benign course with resolution of signs and symptoms within 3 months but occasionally the jaundice can take a year or more to resolve. Progression to cirrhosis is uncommon. Some patients may develop a syndrome resembling primary biliary cirrhosis. The mechanisms of drug-associated cholestasis are uncertain but may arise from alteration of bile formation within the hepatocyte or bile excretion at the level of the canaliculus or the extrahepatic ducts. Histological examination of the liver may be helpful in classifying the types of jaundice but the diagnosis of drug-induced cholestasis is usually one of temporal association and exclusion of other causes.