Acetaminophen sees ups and downs

Acetaminophen (paracetamol) has been in the news lately. One study found that liver damage (hepatotoxicity — measured by ALT(alanine aminotransferase) levels in this study) can occur if someone takes it at the maximum label-recommended amount for two weeks.

However, a meta-analysis published in the July 2006 issue of ??British Journal of Pharmacology?? suggests a chemo-protective effect against ovarian cancer. In other words, a review of eight studies suggested that women taking acetaminophen have, in retrospect, a lower risk of ovarian cancer. However, this needs to be evaluated in a prospective way before anything definitive can be said.

Acetaminophen is normally a safe compound. It is normally metabolized in such a way as to reduce pain and otherwise be nontoxic. However, if the primary metabolic pathway is overwhelmed (as in when you have an overdose of acetaminophen, perhaps from several sources as the compound is in over 300 over-the-counter drug products), a secondary metabolic pathway (if you’re interested, it’s mainly the CYP2E1 enzyme) turns acetaminophen into a toxic quinone. Glutathione can be used to detoxify this metabolite, but if supplies are depleted then liver poisoning results.

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