Should tylenol be avoided as a morning-
after cure for night-before drinking?
Acetaminophen - the active drug in Tylenol -
is bad news for the liver if you take too much of it.
The same is true for alcohol. So together,
do they join forces to really mess things up for you?
In many cases the answer is: "yes," but interestingly,
the science behind this drug cocktail combination is not as obvious as you
might think.
Both acetaminophen and ethanol -
the active ingredient in alcoholic drinks - are removed from your body
through the process of metabolism.
When faced with a substance that's hard to handle,
your body produces enzymes to transform it into chemicals
that are easier to get rid of. And as we're rather efficient organisms,
it's not surprising that there are usually multiple metabolic pathways
for getting rid of tough substances like acetaminophen and ethanol.
The trouble is some of these pathways lead to intermediate chemicals that
are in themselves harmful.
This is what happens with acetaminophen. Acetaminophen is metabolized in the
liver quite effectively
through three different pathways. One of these involves an enzyme named
CYP2E1 - as you can see,
toxicologists have a flair for the dramatic when naming
substances! As CYP2E1 metabolizes acetaminophen
it forms the rather toxic compound NAPQI -
this is not something you want to have floating around your body.
Fortunately, the NAPQI
is rapidly dealt with by a powerful antioxidant -
going by the name of glutathione or GSH. This is
all good news anyone taking tylenol. But the kicker
is that the body can only produce so many of these antioxidants.
And so when the antioxidant GSH is all used up,
the toxic in a NAPQI begins to build up,
And liver cells start to die. So what has this got to do with
alcohol consumption?
Ethanol is similarly dealt with in the liver by the same CYP2E1
enzyme.
Which means that if you have both ethanol and acetaminophen in your system,
there are competing demands for a limited supply of the enzyme.
And this is where things get interesting. If you
Aren't a regular drinker, when you do have a drink
your liver will start using CYP2E1 to get
rid of the ethanol. Now, if you pop a couple of Tylenol a few hours later
to take the edge off a hangover, the chances are that there is not going to be
that much CYP2E1 left to handle it, as the ethanol has mopped up most of
what your body can produce.
Instead, the alternative acetaminophen
metabolic pathways kick in. As a result,
less if the toxic NAPQI is produced, and some other toxic side effects of
acetaminophen are suppressed.
In other words, the science indicates that the occasional drink
may actually decrease the very real dangers
of acetaminophen overdose.
But if you drink a lot and drink regularly,
things look very different. In this case,
you've trained your body to produce more CYP2E1 and to produce it
more regularly.
which means that at any given time, there's more of it likely to be around to
transform
acetaminophen into the harmful NAPQI.
Even worse, ethanol reduces the rate at which the
NAPQI-reducing GSH is produced,
and liver damage becomes more likely.
The bottom line is that taking multiple drugs together
can have complex and not always obvious consequences.
In this case, the science suggests that an occasional night of social drinking
with friends might
actually curb the potential harm associated with taking too much
acetaminophen.
On the other hand, combining acetaminophen with a chronic drinking
habit or
binge drinking is most definitely bad news for you liver.
Of course, as a safer alternative you could always
ditch the tylenol for some other painkiller.
Or even ease back on the ethanol. Now there's
a radical idea!