Term
| where is the primary site of metabolism in the body? |
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Definition
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Term
| what enzymes in the liver catalyze the oxidation of organic substances? |
|
Definition
| cytochrome P450 superfamily enzymes |
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|
Term
| where do most drugs undergo elimination? |
|
Definition
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Term
| at what creatinine clearance does drug dosage normally need to be adjusted? |
|
Definition
|
|
Term
| when is it okay to overestimate renal function in eliminating drugs? |
|
Definition
| in elderly or cachectic pts whose Cr level is <1 |
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Term
| for what PK parameters do we have population averages aka "textbook" PK? |
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Definition
half life
Vd
protein binding |
|
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Term
| what population do "textbook" PK values account for? |
|
Definition
| healthy adults (and sometimes children) |
|
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Term
| what are some things to remember about neonates in PK parameters? |
|
Definition
-immature skin and increased skin hydration = increased absorption of topical products
-increased extracellular fluid = increased Vd of H2O soluble drugs
-metabolic pathways mature at different times
-GFR, tubular secretion and reabsorption immature at birth |
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Term
| what are some things to remember about elderly in PK parameters? |
|
Definition
-skin thinning = inc. absorption of topical products
-increased adipose tissue = inc. Vd of H2O soluble drugs
-age related changes in renal fxn = decreased GFR |
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Term
| what percentage of hospital admission have been attributed to drug-drug interactions? |
|
Definition
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Term
| what factors affect drug absorption? |
|
Definition
-drug A affects drug B
-chelation
-pH changes |
|
|
Term
| what factors affect drug distribution? |
|
Definition
-binding site competition (albumin)
-disease state alteration in plasma proteins, fluid status, adipose |
|
|
Term
| what factors affect drug metabolism? |
|
Definition
-hepatic metabolism
-cyp 450 enzymes (induction and inhibition) |
|
|
Term
| what factors affect drug elimination? |
|
Definition
-competition for pathways
-primarily renal factors |
|
|
Term
| what is the only factor that steady state is dependent on? |
|
Definition
|
|
Term
| what are the 4 types of drug interactions? |
|
Definition
- Drug-drug
- drug-nutrient
- drug-disease state
- intentional vs unintentional |
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Term
| how does aspirin affect warfarin absorption? |
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Definition
| aspirin competes for protein binding sites of warfarin, which increases free warfarin = increased active drug |
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