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Pharmacokinetics of Ethanol

ebola?

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the metabolic function of alcohol

hey.
at various times, I've heard it purported that the function for the metabolism of ETOH is linear, approximating 1 beer/hr in the average individual. On the other hand, the metabolic function for most other drugs is exponential and may be described in terms of half-lives. So...what is so special about alcohol and/or alcohol dehydrogenase?

ebola
np: cex
 
The half-life is just the time it takes to eliminate half of the drug in your system. If the rate of metabolism of alcohol was 1beer's worth/hr, then the half life would be 30 minutes (in terms of beers).
 
well, yes, I'm aware of that.
however, it was explained to me (I forget where), that the metabolic function for alcohol is linear and thus could not be described in terms of half lives. for example, regardless of whether the average person has 3 or 6 shots within 5 minutes, she will still metabolize roughly 1 shot after 1 hour.

ebola
 
Well.. I'm not sure if this is what you're asking about or not.. but you only have so many enzymes that oxidize alcohol. Once they are saturated, alcohol levels just build up until the enzymes are freed up to oxidize more (aside from the alcohol that you excrete in urine, that is).

The amounts of these enzymes don't rise & fall with the alcohol levels in your body. So once they are maxed out, it will break down at a fairly constant rate.
 
ah...so this is just as my girlfriend suggested.
since the effective dosage of alcohol is rather high, it will saturate the alcohol dehydrogenase present in the body while other drugs, which are effective at lower dosages, tend not to saturate the enzymes responsible for their catabolism.

ebola
 
Yup, exactly, the non-linear section of the alchol curve is in the less than a beer, kinda range, then you saturate. Ahh pharmacokinetics, it's so nice..... but boring.
 
I'm amused...sort of.
my next task will be figuring out why this same topic got 80ish views but no replies in "Other Drugs". :)

ebola
np: brian eno
 
Another point to consider: If you use ethanol habitually, your body will increase the amount of alcohol dehydrogenase present. I would guess...... increasing the speed of break down. I doubt it has a huge impact.
 
Actaully, it is unlikely that alchol dehydrogenase activity increase in chronic alcohol use (even at sub 'alcoholic' doses), thought cyp2E1 metabolises ethanol to a degree, and is induced by ethanol.
 
Huh.... well it has been awhile sence I have had to sit through a lecture. One would think that an alocoholic's tollerence to higher and high amounts would be, in part, due to increased enzyme activity. But you are one hell of a smarty pants, and I am not :)
 
right, but this would not necessarily be the case.
tolerance could also occur via changing receptor densities of various GABA, NMDA, etc. receptors in the brain.

ebola
 
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