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11 Cards in this Set
- Front
- Back
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what's the chemical defense hypothesis? exceptions?
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it's that the body needs a system to chemically alter the things that come in to it to make sure they leave the body.
with drugs, this is generally making them more water soluble for secretion. there are some exceptions - parathion, sulfanilamide, imipramine are all made more active by becoming more water soluble by the body. |
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what are some specific mechanisms of metabolism of drugs?
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type 1 and type 2.
Type 1 is fairly simple: it's reduction, oxidation, or hydrolysis. There are some specific enzymes that can do this. some are specific, some are non-specific. type 2: this is hooking up a small molecule to the drug to help get rid of it. considered 'detoxificatoin' also, if type 1 and 2 happen together, type 1 happens first. |
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name some specific type 1 enzymes:
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alcohol dehydrogenase - good for methanol, steroids too.
xanthine oxidase - for purine metabolism. amine oxidase: two kinds. monoamine oxidase (MAO) - break up catecholamines, norepi, etc. diamine oxidase - works on HISTAMINE (test question). reductases: azoreductases and nitroreductases also, hydrolayses: includes acetycholine esterase, succinylcholine, and procane. di |
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what larger system is p450 a part of?
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mixed oxidation. to do this, you need a reducing enzyme and a source of oxygen. without either, the system stops working. AKA general non specific pathway
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what's the rate limiting step in the general, non specific pathway in the liver?
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P-450.
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how does P450 work?
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needs to be REDUCED by p450 reductase. so, sometimes the rate limiting step is not haivng enough p450 in the reduced form.
adding more p450 reductase sometimes but not always increases the rate of metabolism. |
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what's one way you can get a tolerance to a drug?
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induction over a long time (weeks!) of p450. Can come from phenobarbatol, rifampin, or insectisides.
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is there only one p450?
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no - we need to know about 3.
cyp1 cyp2 and cyp3 |
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talk about cimetadine - inducer or inhibitor of p450?
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cimitedine is an inhibitor of p450, specifically the CYP-2 family.
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what does disfulfiram do?
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inhibit 2e
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what does ethanol do?
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acute can be an inhibitor of p450, which is why it's bad to drink and take drugs.
over time, it can induce p450 and be a reason that you get tolerance. can get hyper from this - treat diabetics with tolbutamide. if chronic drinking, the drug doesn't work as well. |
