How Tylenol damages the liver
Tylenol (acetaminophen) primarily harms the liver, its main organ of toxicity. Overdose depletes glutathione, leading to buildup of the toxic metabolite NAPQI, which causes hepatocyte necrosis. Single doses over 4g or chronic use above 3g daily in adults risks acute liver failure; symptoms include nausea, jaundice, and elevated ALT/AST levels. The FDA warns it's the leading cause of acute liver failure in the US, with 50% of cases from unintentional overdose.[1][2]
Does it affect kidneys?
Kidney injury occurs mainly with overdose or chronic high doses, causing acute tubular necrosis. Risk rises in dehydrated patients or those with pre-existing kidney disease. Studies link prolonged use (>4g/day) to chronic kidney disease progression, though less common than liver effects.[3]
Heart risks with long-term use
Extended high-dose use correlates with slight increases in hypertension and cardiovascular events in observational data, possibly from prostaglandin inhibition. No strong causal link at recommended doses.[4]
Rare effects on other organs
Pancreatitis and gastrointestinal bleeding appear in overdose cases. Blood disorders like thrombocytopenia are very rare.[2]
Sources
[1]: FDA Drug Safety Communication on acetaminophen (fda.gov)
[2]: NIH LiverTox database on acetaminophen (ncbi.nlm.nih.gov)
[3]: Systematic review in Kidney International (kidney-international.org)
[4]: BMJ cohort study on acetaminophen and CVD (bmj.com)