Hepatotoxins

Hepatotoxins are substances capable of causing injury to the liver. They include pharmaceuticals, environmental chemicals, industrial solvents, mycotoxins, and certain plant or herbal compounds. Hepatotoxicity can be dose dependent, as with acetaminophen and chronic alcohol use, or idiosyncratic, occurring unpredictably in susceptible individuals. The liver injury may be hepatocellular, marked by elevations of alanine and aspartate aminotransferases; cholestatic, with elevations of alkaline phosphatase and bilirubin; or mixed in pattern.

Common examples encompass acetaminophen, ethanol, methotrexate, isoniazid, halothane, carbon tetrachloride, aflatoxins, and pyrrolizidine alkaloids. Some herbal products have been implicated as well. Mechanisms include direct cytotoxicity from reactive metabolites, oxidative stress, mitochondrial injury, and immune-mediated processes; the pattern depends on the toxin and exposure.

Diagnosis rests on history of exposure, clinical presentation, and laboratory evaluation. Liver tests are used to classify injury and monitor recovery; imaging can exclude other causes, and liver biopsy may be required in ambiguous cases. Management focuses on stopping the offending agent and providing supportive care; specific antidotes, such as N-acetylcysteine for acetaminophen toxicity, can be life-saving. In cases of severe acute liver failure, transplantation may be necessary.

Prevention emphasizes careful drug dosing, monitoring when liver disease is present, avoidance of hepatotoxins in high-risk individuals, and regulatory measures to limit exposure and provide warning labels.