NB F3 S1 Acetaminophen Toxicity

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NB F3 S1 Acetaminophen Toxicity

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ord
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07/02/06 - 07:51 PM

A 20 year old woman ingests 100 tablets (500 mg per tablet) of acetaminophen in a suicide attempt; she does not lose consciousness. She seems healthy for the next 2 days and then develops massive hepatic failure. Which of the following is the primary mechanism responsible for the hepatic failure?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

a)depletion of intracellular reduced glutathione
b)formation of excessive superoxide in the hepatocytes

c)inhibition of adnenylyl cyclase
d)inhibition of ATPase dependent transport
e)stimulation of cytochrome oxidase

A?

star1
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07/02/06 - 07:54 PM

yes A

Musuq
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07/03/06 - 02:17 AM

a)depletion of intracellular reduced glutathione

The analgesic acetaminophen causes a potentially fatal, hepatic centrilobular necrosis when taken in overdose.

The findings indicate that acetaminophen is metabolically activated by cytochrome P450 enzymes to a reactive metabolite that depleted glutathione (GSH) and covalently bound to protein.

It is shown that repletion of GSH prevented the toxicity. This finding led to the development of the currently used antidote N-acetylcysteine.

The reactive metabolite was subsequently identified to be N-acetyl-p-benzoquinone imine (NAPQI). Although covalent binding has been shown to be an excellent correlate of toxicity, a number of other events have been shown to occur and are likely important in the initiation and repair of toxicity.

Diego Casali
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07/03/06 - 03:10 AM

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