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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 5 of 5. This is the beginning of the thread.
Posted by Quintal on September 28, 2007, at 14:21:06
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Caffeine Plus Acetaminophen May Damage Liver
A mix of acetaminophen and caffeine may cause liver damage, especially in heavy caffeine drinkers, according to a study conducted at the University of Washington, Seattle. Researchers have found that caffeine can triple the amount of a toxic byproduct of acetaminophen, N-acetyl-p-benzoquinoneimine (NAPQI), an enzyme produced while breaking down the medication. The enzyme is also responsible for liver damage and failure in most toxic alcohol-acetaminophen interactions.
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Posted by KayeBaby on September 28, 2007, at 21:56:29
In reply to Caffeine Plus Acetaminophen May Damage Liver, posted by Quintal on September 28, 2007, at 14:21:06
Good to know. I take excedrin extra strength (acetaminophin/caffeine/aspirin) and wash it down with coffee all the time.
Thanks!
Kaye
Posted by Larry Hoover on September 28, 2007, at 22:33:44
In reply to Caffeine Plus Acetaminophen May Damage Liver, posted by Quintal on September 28, 2007, at 14:21:06
> __________________________________________________
>
> Caffeine Plus Acetaminophen May Damage Liver
>
> A mix of acetaminophen and caffeine may cause liver damage, especially in heavy caffeine drinkers, according to a study conducted at the University of Washington, Seattle. Researchers have found that caffeine can triple the amount of a toxic byproduct of acetaminophen, N-acetyl-p-benzoquinoneimine (NAPQI), an enzyme produced while breaking down the medication. The enzyme is also responsible for liver damage and failure in most toxic alcohol-acetaminophen interactions.
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>
> QNAPQI is quenched by glutathione, so the only way that NAPQI could accumulate is that caffeine somehow messes with glutathione levels, and/or regulatory enzymes. I'd expect that the same preventative for acetaminophen toxicity in overdose would be just as efficacious here: n-acetyl cysteine. Equal milligrams dosing of acetominophen (paracetamol) and n-acetyl-cysteine would ensure safety, even in the presence of caffeine. N-acetyl-cysteine is a precursor to glutathione, reacts with spent glutathione to restore its antioxidant status, and undergoes similar quenching reactions on its own.
Lar
Posted by Quintal on September 28, 2007, at 23:07:25
In reply to Re: Caffeine Plus Acetaminophen May Damage Liver » Quintal, posted by Larry Hoover on September 28, 2007, at 22:33:44
Right, thanks for that Larry. I agree about the N-acetyl-cysteine supplement, at least it makes sense in theory. I hadn't really given the mechanism much thought, though I did wonder if caffeine might be interfering with the enzymes that metabolize acetaminophen in some way, since the excerpt does say the amount of NAPQI was tripled while breaking down acetaminophen. If that's accurate then it seems to suggest that caffeine may induce the 'cytochrome P450' enzyme that metabolizes acetaminophen into NAPQI. According to this table caffeine is an FDA acceptable substrate for in vitro experiments. I'm not exactly sure what that means, but I'm guessing that caffeine must be a fairly strong and reliable inhibitor or inducer of P450, in this case I'd suspect it is an inducer. http://medicine.iupui.edu/flockhart/table.htm
I suppose if you're a rapid metabolizer this means you have more of a certain enzyme than the average person? If so, this is a concern for me since I can feel the euphoric effect of tiny amounts of codeine, so I guess this means I may also be producing an abundance of NAPQI along with every dose of paracetamol? Time for the N-acetyl-cysteine supplement methinks.
__________________________________________________1: Can Fam Physician. 2007 Jan;53(1):33-5.Click here to read Links
Comment in:
Can Fam Physician. 2007 Jun;53(6):1005; author reply 1005-6.Safety of codeine during breastfeeding: fatal morphine poisoning in the breastfed neonate of a mother prescribed codeine.
Madadi P, Koren G, Cairns J, Chitayat D, Gaedigk A, Leeder JS, Teitelbaum R, Karaskov T, Aleksa K.QUESTION: Recently a newborn died from morphine poisoning when his mother used codeine while breastfeeding. Many patients receive codeine for postlabour pain. Is it safe to prescribe codeine for nursing mothers? ANSWER: When a mother is an ultrarapid metabolizer of cytochrome P450 2D6, she produces much more morphine when taking codeine than most people do. In this situation, newborns might be exposed to toxic levels of morphine when breastfeeding. Options to reduce this risk include discontinuing codeine after 2 to 3 days of use and being aware of symptoms of potential opioid toxicity in both mothers and newborns.
PMID: 17872605 [PubMed - indexed for MEDLINE]
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Posted by cactus on September 29, 2007, at 19:04:16
In reply to Re: Caffeine Plus Acetaminophen May Damage Liver » Larry Hoover, posted by Quintal on September 28, 2007, at 23:07:25
Sh*t, I have been free styling on caffeine since I quite drinking 5 months ago but luckily I don't take much Paracetamol/Acetaminophen. I'll make sure to watch out for that, thanks Q
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