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26 Cards in this Set
- Front
- Back
Branches of pharmacology
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pharmacodynamics - action of drugs on body
pharmacokinetics - fate of drugs in body toxicology - study of undesirable, adverse effects of drugs pharmacogenetics - genetic factors contributing to drug response/outcomes |
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drug size and molecular weight (MW)
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MW b/w 100 to 1000
- too small: drugs not selective - too large: poorly absorbed & distributed |
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ex of drug size & MW and action in body
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BBB prohibits access of large hydrophilic molecules into CNS
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types of drug-receptor bonds
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1. covalent bonds (usual irreversible)
2. electrostatic bonds (b/w cation/anion) 3. weak H2, van der Waals, hydrophobic bonds |
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What are the main factors determining the movement of drugs in the body
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charge of drug and medium
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Fick's law determines what?
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movement of molecules through membranes and other lipid structures
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Many drugs are found to be either:
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weak acids or weak bases
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What determines the fraction of the molecules (drug) that are charged/uncharged, as well as the absorption of the drug across the lipid membrane
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the pH of the medium
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What does the Henderson-Hasselbalch equation predict?
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The propensity of a drug to carry a charge under different physiological conditions (helps determine absorption/excretion)
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Ionized drugs are more:
Non-ionized drugs are more: |
water soluble
lipid soluble |
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Since membranes are composed of lipids, what types of drugs are absorbed, and which are excreted?
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1. non-ionized - absorbed
2. ionized - excreted |
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The ionized/non-ionized form of drugs are determined by:
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1. pH of environment
2. whether drug is weak acid or weak base |
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An acid in an acid environment favors:
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absorption (lots of acidic form, so they shift to non-ionized form; non-ionized form favors absorption)
AAA |
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An acid in an alkaline environment favors:
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excretion (lots of nonprotonated molecules, so shift to the ionized form to donate protons; ionized form favors excretion)
ABE |
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A base in an acidic environment favors:
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excretion (lots of nonprotonated molecules, so they shift in direction of ionization; ionized form favors excretion)
BAE |
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A base in a basic/alkaline environment favors:
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absorption (lots of protonated molecules, so they shift in the direction of non-ionized form; non-ionized form favors absorption)
BBA |
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Henderson Hasselbach equation
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log (protonated/unprotonated) = pKa - pH
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Most drugs are freely filtered at the ________, but lipid-soluble drugs can be rapidly reabsorbed from the _______________.
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glomerulus; tubular urine
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Weak acids are _____ faster in basic urine; and ______ faster in acidic urine.
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excreted; reabsorbed
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Weak bases are excreted faster in _____ urine; and reabsorbed faster in _____ urine.
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acidic; basic
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Acidify urine by giving
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ammonium chloride
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alkalinize urine by giving
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sodium bicarbonate
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Fick's law of diffusion
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rate = (c1-c2) x (perm coefficient/thickness) x area
interpretation: drugs absorbed faster from organs w/ large SA and thin membranes |
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What other types of permeations, aside from pH, determines absorption
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- aqueous diffusion
- transport by special carriers - endocytosis/ pinocytosis |
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1. Which of the other types of permeations is governed by Fick's law?
2. Which of the other types is not? |
1. aqueous diffusion
2. transport by special carriers |
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What criteria must be considered in determining route of administration:
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1. drug properties and profiles
2. drugs site of action 3. condition and age of patient 4. rapidity and duration of drug effect required 5. convenience, cost, availability |