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Comment by DanBC | Hacker News Reader

> For some reason, the snakes are almost uniquely sensitive to acetaminophen, the active ingredient in the ubiquitous over-the-counter painkiller. If you can get a tree snake to eat just 80 milligrams, you can kill it. That's only about one-sixth of a standard pill — pigs, dogs and other similarly sized animals would have to eat about 500 of them to get into any trouble.

Just a quick note: Paracetamol is a great and useful painkiller. It's safe if taken properly. But it is dangerous when taken in overdose. People who've taken an overdose of paracetamol must get medical attention as soon as possible, even if they feel well.

A standard UK tablet is 500 mg. 15 tablets - 7.5 g, is enough to be lethal.

People accidentally overdose and die from paracetamol. You don't do that with "500 of them to get in any trouble".

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Indeed, paracetamol (as most of the world calls it) is highly toxic to many species - while people have a small tolerance to it, there are many documented cases of people suffering fatal liver damage through doses only just above the maximum daily dose of, typically, 4g. Domestic cats can die from simply licking tablets due to their extreme sensitivity - which sounds more sensitive than snakes, making them not 'unique' either.

I'm extremely sceptical of a claim of '500' published in that context - to the point of thinking that sounds positively reckless and liable to make people take extremely dangerous doses in the belief that huge numbers are needed to present any risk.

In the UK, packages can only be purchased in maximum quantities of 16 tablets and maximum 2 boxes per purchase to reduce the risk of both accidental and deliberate overdosage (with a significant decrease in overdose incidents as a result).

This American Life recently did an episode on how even a few tablets over the recommended dose can cause serious harm in some people: http://www.thisamericanlife.org/radio-archives/episode/505/u...

Another significant danger is posed to anyone who has been drinking in the days before taking the drug. The enzymes which process alcohol also process the paracetamol, and will be present in elevated levels, potentially causing liver damage. What is important is that the danger is caused by taking paracetamol some time (hours or days) after having consumed alcohol; most people think that paracetamol is only dangerous when taken with alcohol.

Any source on the specific length of time after drinking one should avoid paracetamol?

I have never been able to find good data on this, but from what I have gathered, the effect depends on how much you have been drinking (drinks/day), and how long you have been doing it (# of days). It does seem that gathering valid data on this would be very useful, but I am not sure how one could do a randomized control trial, when the express goal of doing so would be to measure the harm done by the 'treatment'.

At over 4000mg in humans in a 24 hour period and you overload the first two metabolic pathways in the liver for Acetaminophen, forcing it to go through another pathway where a toxic by-product is made by the body.

Ingestion of alcohol can drop this approximate 4000mg before toxicity is experienced down to about 2000mg.

I know this because I've been skating awfully close to that 4000mg ceiling for about one week now. I had my tonsils removed last Wednesday and need at least 20mg of oxycodone per 4-6 hour people to handle the pain. Unfortunately every 10mg of oxycodone is bundled with 325mg of acetaminaphen.

I really hope lobbying by Tylenol is eventually reversed and oxycodone and other opiates can be pressed into pills without acetaminaphen. It's ridiculous that I and others get close to poisoning our livers because of unnecessary bundling of drugs.

(FWIW I weight ~240 lbs)

Virtual hug. I had my tonsils removed as an adult too. Not fun. I've been thru a lot. I thought "Ha, cake walk, no prob." Wrong.

Thanks. It's pretty brutal. I've lost 25 lbs in 7 days already from it.

There are two big problems with acetaminophen as a medicication. One, the theraputic dose is far too close to the lethal or hazardous dosages. Two, because it's been in use for so long there ends up being a lot of it in many medications, though some people don't appreciate that.

For example, let's say you are feeling under the weather with typical flu symptoms including body ache and congestion. So you decide to take some nyquil. But you're feeling so achy that you decide to take some acetaminophen as well. And you drink a glass of water with some alka-seltzer to settle your stomache before bed. Not such crazy things to do. And maybe you inadvisably decide to take larger doses than you should, because you feel really crummy and you want to feel better (and more drugs = stronger effects, right?) So you take a triple dose of nyquil and a double dose of acetaminophen. Except now you've 4,000 to 5,000 mg of acetaminophen. Then tack on the extra half gram from a double dose of alka-seltzer plus severe cold & flu (which maybe you forgot was the only variety you had in the cabinet) and you are well into dangerous territory. Combine that with re-upping doses at less than the recommended interval and things can get scary very fast.

I wrote to the author and this has now been reworded: "pigs, dogs and other similarly sized animals would have to eat about 500 of the baited mice to get a lethal dose".

Thank you. It's really nice to hear that they listened and did something.

And I'm grateful to you for actually doing something!

I find that reporters tend to be very good for changes after an article is published -- much easier to fix mistakes at that point than before publication, in fact, since they no longer have an editor breathing down their neck.

People reading/commenting seem to be misreading the 500 number. Note it's comparing to the previous number 80mg, it's not '500 pills' or '500 tablets' it is 500mg.

Which is consistent with the remaining text and known literature.

It says 500 of them. I've never heard a unit of measure like "mg" being referred to it as "them". So it makes sense to interpret that as "pills".

Them refers to bait doses. They are not dropping pills out of the helicopter, they are dropping bait and people are worried about other creatures eating the bait.

Which is fair, but seeing as how many people were confused (I was), it's probably not a good wording.

But it doesn't? If the bait dose is 80mg, then 500 doses would be 40,000mg. I think they must mean 500mg -- that's consistent with the toxic dose being 200mg/kg in dogs and 10mg/kg in cats [1]. The phrasing is super bad, I wonder if it was altered by a copy-editor who added a unit but misunderstood the intended meaning.

[1] http://www.ebvet.com/forum/viewtopic.php?f=9&t=383

> I wonder if it was altered by a copy-editor who added a unit but misunderstood the intended meaning.

Someone linked to a video of this story, and if you watch it the original quote was very clearly bait doses.

It's still, in addition to being irresponsibly badly worded, inaccurate.

Tyenol's own research suggests an LD50 for dogs of around 1180–1450mg/kg. In other words, you'd only need around 30,000mg to probably kill a medium sized dog within a short time period, which is about 375 "bait doses". Needless to say, they can "get into trouble" on smaller doses. The manufacturer considers less than 100 "bait doses" to be an "acute overdose" for an adult human.

Sure, the number of poisoned mice a dog would have to eat to suffer even mild liver poisoning is still far in excess of the number of mice a dog is likely to eat, so the implicit point that this isn't likely to poison local large mammals still stands. That doesn't excuse the lack of care in reporting those medical statistics on the part of the author/editor, however.

Them, in this case, refers to the dosed mice and the fact that an animal would have to consume 500 of the mice to run into any toxicity issues.

(At least that is my reading of the poorly worded sentence)

The article needs to make that much clearer than it is - because most people reading that article are going to be confused about the number.

I'm curious, how do people accidentally overdose 15 tablets ?

By not reading the label when they take multiple cold and flu remedies all containing paracetamol to speed up their recovery.

Or reading articles which say you need 500 for there to be any risk.

Or by misreading articles. Which is also how people overdose - by misreading bottles.

The article says 500 bait doses, not 500 pills.

Bottles are usually a lot clearer than this article paragraph.

Most people are going to read that as 500 pills, not 500 doses of one sixth of a standard pill.

500/6 pills is also way more than the lethal dose in a dog or human. And I wonder what exactly a "similar sized animal" is, since a pig is ten times bigger than a dog (20kg and 200kg according to Wolfram Alpha).

I guess maybe by mixing different medications that each individually contain high levels of paracetamol? A lot of different over-the-counter medications contain it and if you took 3 separate meds you could quickly end up in that situation.

That's why I always try to buy the pure form of the medication without acetaminophen if possible.

For prescription opiate-based analgesics, You can't buy pretty much any of them in acetaminaphen-free form in the US.

From the bottle of acetaminophen on my desk:

Take 1 or 2 tablets with water, every 4 to 6 hours. If pain or fever does not respond to 1 tablet, take 2 tablets at the next dose."

Now, why wait to take 2 tablets? And maybe your headache is really bad. If 2 are stronger, 4 must be better.... 4 pills every four hours means that in a day you can get 8 grams dosage. Sure, it says "No more than 8", but it's in tiny letters, and most people don't actually realise just how serious the danger is.

16 tablets over the course of the day isn't really what most people think of as a drug overdose for something as "innocent" as tylenol. In addition, some cold medicine has acetaminophen in it, and you might not realize that your cough syrup was contributing to your dosage. Then bam, liver failure.

If you're genuinely curious, there's a really good episode of This American Life on acetaminophen poisoning and the labeling standards set by the FDA.

Link: http://www.thisamericanlife.org/radio-archives/episode/505/u...

The example in TAL's podcast that really got me was the mixup between infant and child tylenol that resulted in the death of a child.

I've gotten in the habit (before I had children) of reading labels and understanding their contents, dosages and concentrations (if only for the amusement that there seems to be only a handful of drugs in boxes that typically take up several meters of store shelf space). However, the situation of the death of that child in the podcast wasn't out of the ordinary. Simple miscommunication between parent and doctor, and the lack of knowledge of how little acetaminophen you really need to overdose.

Specifying dosages as volumes of liquid is dangerous without knowledge of concentration. Better to specify mg of acetaminophen and let people work the math out (maybe that's asking too much).

I honestly don't understand why printing the LD50 isn't mandatory on all warning labels.

It is thought of as harmless and it is in a lot of combo medicine. So you can take a cold/flu medicine with it in it, then some tablets for headache, then maybe another cold med, and my headache is really bad, more headache medicine, I mean it is thought of as harmless.

Also giving children the adult dose.

The ProPublica report referenced by the This American Life episode is one of the best longform pieces I've read all year [1]. It contains stories related to your question. One memorable example was from parents that inadvertently lethally overdosed their son over a period of a week via Tylenol Sore Throat. The parents testified that they never exceeded the maximum daily dose during the time period where the toxicity built up enough to kill their son.

[1]http://www.propublica.org/article/tylenol-mcneil-fda-use-onl...

I accidentally overdosed on benadryl as a kid. I was given the adult dose by my aunt who meant well but wasn't thinking just read a label and followed the instructions quickly. I was particularly small so I probably had a specifically bad overdose as opposed to another kid my age. I had bad hallucinations and paradoxical insomnia. I say paradoxical because it causes drowsiness at therapeutic doses.

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