Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Alcohol and acetaminophen

  1. May 13, 2013 #1


    User Avatar
    Gold Member

    Edit: sorry for the typo in the title , can't edit

    I looked around on google quite a bit and it's very hard to find precise information on the issue.All I can find is vague warnings like "acetaminophen and alcohol is bad for the liver".

    Anybody have knowledge on just how dangerous the mix can be?

    Suppose you drink a lot of beers (6-9) , go to sleep and then wake up with severe back pain.You take a tylenol , move on with your day , then have to go to a party the very night.Is it safe to drink 6 beers again? How long should you wait between both products intakes?

    I always wondered about these types of situation.
  2. jcsd
  3. May 14, 2013 #2
    Acetaminophen should not be taken with even moderate amounts of alcohol. Both are metabolized in the liver (as are most drugs), and the combination seems to divert some acetaminophen to minor metabolic pathways that result in hepatotoxic byproducts rather than inactive metabolites. In addition both are hepatotoxic at high doses independently so you have both synergistic as well as additive effects. Synergistic effects have also been reported regarding the central nervous system in animal models.

    Having said this, acetaminophen is generally safe for most adults at recommended doses for short periods of time in the absence of alcohol or other substances with which it may interact. Read the label.



    Because people's metabolisms vary quite a bit, I can't give you a recommendation on when you can safely take acetaminophen after drinking alcohol. We also do not give individual medical advice here. Ask your doctor.
    Last edited: May 14, 2013
  4. May 14, 2013 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    It's never a good idea to mix alcohol and other drugs.

    It's possible to take too much acetaminophen. Acute liver toxicity can result, leading to liver failure and death.
  5. May 14, 2013 #4


    User Avatar
    Gold Member

    Yeah of course I understand you guys can't speak about specific cases online.

    The thing I'm trying to understand is when it's considered a mix.If you take one the morning , is it a mix if you take the other during the evening? The day after? 2 days after? a week?

    This is where I think every popular warnings are unclear.
  6. May 15, 2013 #5


    User Avatar

    Staff: Mentor

    Good question, one that I also wondered about in the past. If the problem lies in the metabolism, obvious approach is to not take acetaminophen as long as you feel effects of the alcohol or the post-alcohol affects. But nobody will tell you how long it takes, as to some extent it is an individual reaction. Back-of-the-envelope calculations show that after 8 beers you need around 12 hours to burn the alcohol, and I guess metabolites require another few hours at least. That would mean 24 hours should be relatively safe - with all possible disclaimers.
  7. May 15, 2013 #6


    User Avatar
    Gold Member

    Thanks a lot for the answer!

    It covered the part where you drink before you take the acetaminophen (which make sense since people are likely to take acetaminophen for their headache that was created by their unreasonable drinking) but not the part where you took the acetaminophen before for unrelated reasons and then want to drink some alcohol.

    How long will the acetaminophen stay in your system enough so that if you start drinking it will be considered a mix? Again , I am not naive , I understand it's impossible to compare the exact time from one person to another or even from one person at age X and the same person at age Y.But a general , average time would be nice from the producers of these medications.

    It's pretty mind-boggling that such a common mix isn't explained in more details by whoever is responsible for warning the population.
  8. May 16, 2013 #7
    This is easier to answer. The biological half life of acetaminophen is 2-3 hours for fasting healthy adults with normal liver function. This means half the remaining drug is cleared for every half life. After nine hours (taking the upper end) 1/8 of the original dose remains. To be on the safer side, moderate drinking 12 hours after the last recommended dose is probably pretty safe for most adults. Eating during this period will probably not affect this estimate too much.

    I don't know anything about you and don't need to know because we can't give medical advice here. That's why I advised you to consult your physician. If you do not have normal liver function, all bets are off.

    http://www.tylenolprofessional.com/pharmacology.html [Broken]

    EDIT: As for using acetaminophen after drinking, it's obvious that it depends on what you've been drinking, as well as now much and over what period of time. It also depends on your long term pattern of alcohol use, your weight, your general medical condition, consuming food with alcohol and the kind of food, your state of hydration and your ability to metabolize. Occasional drinkers metabolize alcohol more slowly than habitual moderate drinkers. Habitual heavy drinkers metabolize alcohol more rapidly than moderate drinkers, but this does not prevent long term liver damage. Binge drinking will generally overwhelm the liver's capacity to detoxify alcohol.

    If you feel the need to have at least one alcohol beverage every day, then you probably shouldn't take acetaminophen.
    Last edited by a moderator: May 6, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Similar Threads for Alcohol acetaminophen
A Good Time to Swear Off Alcohol