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17 Cards in this Set
- Front
- Back
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After being absorbed, a drug can be distributed to a combination of the following three places:
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blood; extracellular fluid; tissue
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Bound fraction = ?
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(# binding sites)(total protein concentration) / (#binding sites)(total protein concentration)(dissociation constant)(concentration free drug)
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A drug will become increasingly bound as:
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dissociation constant (KD) becomes lower; free drug concentration becomes lower
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Can bound drug be filtered by glomeruli or diffuse across capillary membranes
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No; only free drug
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What effect does protein binding of a drug have on 1/2 life?
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binding > 1/2 life increases;
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What happens to bound drug as free drug is biotransformed and/or eliminated?
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It rapidly dissociates to become free drug
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What leads to HYPERalbuminemia?
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acute dehydration; rare
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What are the three common causes of HYPOalbuminemia? Give examples of each
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1. Decreased synthesis, e.g. liver disease, malnutrition, malabsorption
2. Loss, e.g. burns, glomerular injury, inflammation 3. Nonspecific, e.g. pregnancy, aging, cardiac failure |
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What do acidic drugs primarily bind to? Alkaline drugs?
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acidic > albumin
alkaline > alpha -1-acid glycoprotein |
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When the protein bound fraction of a drug is greater than or equal to 80%, you should consider what?
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Possibility that a drug interaction will produce a toxic effect
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Why should tetracycline not be given to kids?
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Binds to calcium (teeth), weakens enamel.
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What is significant about glial connective cells?
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They are responsible for the decreased permeability of brain capillaries. important component of BBB
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What are the characterisitcs of a drug that readily crosses the blood brain barrier?
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low ionization @ plasma pH
low binding to plasma proteins high L/W partition coefficient small molecular size |
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What does the term latentiation mean?
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Reversible process of adding lipophilic groups to a molecule; increases penetration of biological membranes, e.g. BBB *once inside target tissue LG removed
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Name the characteristics of fetal capillaries:
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lipid-soluble substances diffuse readily
water-soluble to a lesser degree small molecules diffuse more readily than larger ones large organic ions cross poorly if at all |
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Give 2 examples of drugs that demonstrate the permeability of placental barrier:
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Glycopyrolate and thiopental
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Do most drugs freely pass from mother to fetus?
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Yes, all do.
exceptions: strongly electronegative (heparin), strongly electropositive (neuromuscular blockers), high MW |
