pharm L4 drug action metabolism.txt

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Four characteristics of active drugs
- lipid soluble
- unionized
- plasma protein bound
- not excreted easily by kidneys
What is a highlight of Phase III drugs?

They are secreted back into the gut via P glycoproteins
What % of a drug is commonly an inactive metabolite?

90%
Why is Isoniazid (INH) a special drug when it comes to Phase I & II rxns.?

It goes through phase II then Phase I
What is the main organ that biotransforms drugs?

Liver
what are the roles of Phase I and Phase II rxns on drugs?
- Phase 1: modification of molecule
- Phase II: conjugation of molecule
T/F A Lipid soluble molecule will become less polar after Phase I modification?

F, it will become more polar (less lipid soluble)
What are three outcomes of a drug after a phase II rxn.?
- Larger molecule
- More Polar molecule
- Less biological activity
What happens to drugs with a molecule weight >350 and <350?
- >350 = excreted into bile, metabolized and reabsorbed by gut (possibly)
- <350 = excreted into blood, kidney, and removed
Organ that metabolizes chlorpromazine & Clonazepam?

Intestine
Organ that metabolizes Penicillin-G & Erythromycin?

Stomach (gastric acid)
Organ that destroys Insulin & Polypeptides?

Stomach (Gastric juices)
Organ that inactivates epi & norepi & other catecholamines?

Intestinal Wall
What is a Microsomal Rxn?
- Phase I Rxn
- ** microsomal = chopped ER
What is the bodies main microsomal Rxn?

Cytochrome P450
What does CYP1A2 do in the Cytochrome P450 system?

Metabolizes smoke, acetaminophen, grilled foods, etc...
What is the largest Cytochrome P450 metabolizer of drugs?

CYP3A4
What phase Rxn are non-microsomal metabolites that are non-inducible?

Phase 1
Are Esterases/Amidases microsomal or non-microsomal?

Non
2 Examples of Esterase and Amidase?
- Pseudocholinesterase - genetic polymorphism
- Lidocaine
Are Monoamine oxidase non-microsomal or microsomal?

Non
Main example of monoamine oxidases?

Endogenous amine - Tyramine (cured foods)
Are Alcohol & aldehyde dehydrogenase non-microsomal or microsomal?

Non
What is the cellular result of Phase II rxns?
- Large molecule
- More polar
- inactive
What is the only Phase II rxn that is microsomal and inducible?

Glucoronidation
Name the 7 types of Phase II Rxns
- Glucoronidation
- Acetylation
- Methylation
- Glutathione conjugation
- Glycine conjugation
- Sulfate conjugation
- Water conjugation
How does enterohepatic circulation help with drug reabsorption?
- Bacterial enzymes split conjugate for reabsorption
- increase drug half-life
Do you increase or decrese a drug dose for a fast or slow metabolizer?
- Fast metabolizer = more drug
- Slow metabolizer = less drug
What are four drugs that require biological variation?
- INH
- Mephenytoin
- Warfarin
- Succinylcholine
Why do young children react differently to drugs?
- Permeable BBB
- Decreased liver function
- Decreased renal excretion
In the elderly, what is the path of reduced drug metabolism?

Kidney > phase I > Phase II in Liver
What is the Sex difference for ethanol?

Ethanol concentration in males is higher than females b/c we have more water
What are the two main diseases that modify drug metabolism?

Liver and Renal disease
Common pathway of metabolites in kidneys?
- Glomerular filtration
- Secretion or reabsorption
- Diffusion across tubular epithelium

Author

kepling

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Card Set

pharm L4 drug action metabolism.txt

Description

pharm L4 drug action metabolism

Updated

2011-09-21T19:22:44Z

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