I originally posted this to alt.suicide.holiday but it was recommended
that I try you guys instead:

My friend insists that Ny-Quil can be deadly if enough is taken -- he
suggested something like 20-30 of the Night-time gelcaps would do someone
in.  Being a NORMAL user of Ny-Quil :), I checked the 'ingredients' and
have a very hard time believing it.  They are:

250 g acetaminophen
30 mg Pseudoephedrine HCl
10 mg Dextromethorphan HBr
6.25 mg Doxylamine Succinate

(per softgel)

Can someone settle our bet (a package of Ny-Quil of course :) -- what
effect would 20-30 of these babies have?

*-Nathan-*

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The acetaminophen is the agent of concern in overdose of this
OTC medication.  A single dose of acetaminophen of 10 grams or greater
can cause hepatotoxicity, and doses of 25 grams or more are
potentially fatal from hepatic necrosis.  If I recall
correctly, the metabolism of acetaminophen at high doses
involves N-hydroxylation to N-acetyl-benzoquinoneimine, which
is a highly reactive intermediate, which then reacts with
sulfhydryl groups of proteins and glutathione.  When hepatic
glutathione is used up, this intermediate then starts
attacking the hepatic proteins with resulting hepatic
necrosis.  The insidious part of acetaminophen toxicity is the
delay (2-4 days) between ingestion and clinical signs of liver
damage.  This is NOT a nice way to die.

As to taking 20-30 of these tablets, that comes to 5-7.5 grams
of acetaminophen.  In a normal {*filter*}, this would probably
cause nausea, vomiting, abdominal pain, and loss of appetite.

Bob Schmieg

[Partial deletion]

Nice explanation except that it isn't N-hydroxylation that causes the
formation of the N-acetyl-p-benzoquinone imine (NAPQI), but rather a
direct two-electron oxidation. In addition, there is one school of thought
that contends that oxidative stress rather than arylation of protein
is the more critical factor in the hapatotoxcity of acetaminophen.  

As far as drug toxicities go, acetaminophen has and continues to be one
of the most intensely scrutinized. An excellent recent review of the topic
can be found in:

        Vermeulen, Bessems and Van de Straat.  
        Molecular Aspects of Paracetamol-induced hepatotoxicity and its
        Mechanism-Based Prevention. Drug Metabolism Reviews, 24(3) 367-
        407 (1992).

        (Acetaminophen is known as paracetamol in Europe)

I couldn't agree with you more about what an awful way to die a toxic
dose of acetaminophen causes.  I've heard a number of descriptions by
physicians associated with poison control centers, and they describe a
lingering very painful death.

-Gary-

Yargh!

I'd certainly say that would do a person in!  But not necessarily as
quickly as the person would like.

The pseudoephedrine HCl (the ingredient in Sudafed, a common decongestant)
would cause a lot of anxiety, palpitations, and would cause the heart rate
to increase.

The dextromethorphan, a cough medicine, doesn't cause much sedation.

I don't know about the doxylamine, except I believe it is an antihistamine.

Probably 20-30 gelcaps would be enough to cause you to vomit.

And the tylenol--that amount of tylenol would cause liver damage.  And
liver damage is a slow {*filter*} way to die.

I don't recommend it.

"The chief function of the body is to carry the head around."
                                        --Albert Einstein

What you need here is a dose of reality, not a dose of
Ny-Quil. I suggest you weigh out 250g (8.8 oz) of *any powder*
at home, assuming you have a scale of some kind.
Try some table sugar. How *large* is 250g of powder?
Hint: a fair bit bigger than 1 gel-cap. How about this.
Are you a weight-lifter? Can you bench-press a bottle
of 100 gel-caps? According to the above, 100 gel-caps
is 25kg, or >50lb. Does that sound right to you?

That said, I would strongly advise against anyone
consuming 250g of acetaminophen.

:-)
Brian