in pharm drugs fall in to two classes of kinetics. first order or zero order. it deals with their clearance, or how fast the drug is eliminated from the body. first order kinetics is what almost all drugs are. first order drugs are cleared with a constant half-life. this means that they are concentration dependent. the more drug present, the faster it will be cleared. zero-order kinetics means that the drug clearance is constant. it does not have a constant half life. so if you have a huge amount of that drug in your system, it will be eliminated from the body at the same rate is if you had just a little. the drug metabolism pathways are saturated.
I'm going to make this post interactive. take my poll. from your experience with drinking, do you think alcohol is first order or zero order?
4 comments:
Alcohol is definitely zero-order. As Billy Madison once said... "I know from personal experience!"
My guess is that this has something to do with the excretion system (kidneys vs. liver) like for instance, if you drink a gallon of Gatorade, your are going to excrete all of those salts pretty rapidly because your body doesn't need them but if you drink a gallon of whiskey, it will metabolize at the same rate as if you drink an ounce of whiskey because it will get saturated into your blood no matter how much you have.
I just re-read what I wrote and I realize that it made no sense so uhh... scratch that.
Alcohol is mostly zero-order in normal women, mostly mixed model zero and first in normal men. In women who abuse alcohol, it's only a little over half zero-order, the rest is mixed, and for men it's still mostly mixed.
The zero-order is because of ADH and the first order is due to tissues' action on absorption and distribution so that one can vary a bunch.
Correct me if I'm wrong.
This is all based on information that just seemed to come to me after consuming a generous amount of wiskey. Thanks for the idea, Jeffrey.
alcohol is no good to drink right nic?
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