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From: B. Harris)
Subject: Re: Breakdown of ethanol in the body
Date: 30 Apr 1997
Newsgroups: sci.chem,alt.alcohol,

In <>
Konrad Vandegaer <> writes:

>On Sat, 26 Apr 1997, Steinar F. van der Meer wrote:
>> I've read about the breakdown of drugs in the body, and they always
>> refer to a certain halflife of the drug. But I understand that alcohol
>> is digested at a constant rate (about 0,015 % pr hour). Does anyone
>> know why that is so?
>What you quote is NOT a constant rate.  It's a percentage of the total
>from which you should be able to figure out a half-life just like any
>other drug.

   No, what is meant is that the % alcohol in your blood goes down by
015% per hour, or something like that.  Which does amount to a
constant rate.  As somebody pointed out, at levels of alcohol which
drivers have to worry about, metabolism is zero order kinetic, which
means that the enzymes are saturated, and the rate of disappearance of
ethanol in the body is INDEPENDENT of concentration.  Thus,
concentration falls off linearly, not exponentially.  No half-life.

                                          Steve Harris, M.D.

From: (Carey Gregory)
Subject: Re: Question about blood alcohol levels over time.
Date: Thu, 20 May 1999 00:17:43 GMT (Bureaucrat) wrote:

>A man drinks in a bar from 9pm to 2am. He wakes up at 5am, has no
>breakfast, and is subjected to a breathalyzer test at 7am. He is still
>over the legal limit (i.e. his blood alcohol level is at 0.08). The man
>is roughly 5 ft 7 and 145 pounds, aged probably 23-24, healthy and
>athletic, not generally a heavy drinker.
>Since I don't know the rate at which alcohol leaves the body, I'm not
>sure how much this character would have to drink for him to still be
>drunk at 7am. Can anyone help me figure this out? It needs to be this
>precise because these facts are going to be used later on in this script,
>during a court case.

As a general rule, each drink adds .02 to the BAC and each hour that
elapses reduces it by .015 (in a healthy 150 lb. male).  A "drink" is
12 oz of beer, 8 oz of wine, or 1.5 oz of liquor (all about the same
alcohol content).  Adjust accordingly for the reality that most hard
drinks contain more than 1.5 oz.

Real precision isn't possible here because it varies from individual
to individual, and from one time to the next in a single individual
depending on many factors, most notably food in the stomach while he's
drinking.  A meal before or during drinking helps slow absorption, but
this guy's lack of breakfast wouldn't matter much since it's after the
fact when all the alcohol has already been absorbed..

Using the figures given above, the answer is 13 drinks.  The chart
looks like this for 13 drinks between 9pm and 2am:

Time     BAC
10pm	0.037
11		0.074
12		0.111	(legally drunk in all US states)
 1am	0.148
 2		0.185
 3		0.170
 4		0.155
 5		0.140
 6		0.125
 7		0.110	(still legally drunk in all states)
 8		0.095	(legally sober in most states)
 9		0.080	(the legal limit in some states)
10		0.065	(legally sober in all states)
11		0.050
12		0.035
 1pm	0.020
 2		0.005
 3         0.0

Since he's slightly less than 150 lbs, you could round the answer down
to 12 drinks and use the same chart.  Hope this helps.

Carey Gregory

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