alt Hacker NewsThe article kinda glossed over it, but one fact under-appreciated by the general public is just how dangerous acetaminophen overdoses can be.
Scientists often talk about the "therapeutic index" or "safety ratio" of a drug. It's the LD50 (dose at which 50% of recipients die) divided by the effective dose. Common hard drugs like heroin or methamphetamine have a safety ratio of about 6-10 [1]. "Soft" drugs like marijuana or LSD often have safety ratios of about 1000.
The safety ratio of acetaminophen is under 4. A typical dosing schedule for an adult is 4-6 500mg tablets within a 24 hour period [2], for a total of no more than 3g. 7g of acetaminophen can kill you, and 12g is likely to [3]. Acetaminophen is the leading cause of liver failure in the U.S, causing 50% of cases and 20% of transplants.
When they tell you "don't exceed 6 doses daily", they really mean it, and it's across all acetaminophen-containing products. The margin for error is narrower than heroin.
[1] http://politicsofsin.50megs.com/risk/Toxicity.Comparison_Add...
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Thank you - this is correct and cannot be repeated enough, especially in the context of infant and child doses.
In most countries 4g is the upper limit and it is considered perfectly safe within that limit. So 8 500mg pills in 24 hours.
Acetaminophen should be treated with more caution in general. So many people have reacted with shock and upset when I told them that taking Tylenol (or anything with acetaminophen in it like Dayquil/Nyquil) while drinking can cause immediate liver damage.
I didn’t know this until recently either. I grew up on a family where if there was pain, you just take tylenol to deal with it. We always followed the dosage timing and never had issues. So recently when my wife had some chronic pain I suggested taking tylenol but even after two days the pain would not go away and she went to ER. They did a blood check to see if they could find anything. They didn’t find the cause, just suspected food poisoning, but they found her liver enzymes were near dangerous levels. This was even with timing the dosages absed on instructions. Now I am super careful wtih Tylenol.