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23 Cards in this Set
- Front
- Back
Define structure activity relationship |
The steric arrangement of the drug molecule with the receptor and how that contributes to specificity of drug action |
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Name 5 properties of receptors |
1. Specificity? 2. Expected to bind a normal body component 3. May have subtypes 4. Can be desensitized 5. Propagate signal via changing ion transport (iontrophic) or activating second messengers (metabotrophic) |
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Name 3 types of noncovalent bonds |
1. Ionic bonds 2. Hydrogen bonds 3. Hydrophobic bonds (Van der Waals) |
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Define threshold |
The drug concentrated need to elicit an effect |
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Define max efficacy |
The drug concentration beyond which no increase in concentration will lead to a higher percentage of effectiveness |
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Define partial agonist |
A drug not causing a maximal response |
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When can summation and potentiation/synergism be determined with drugs? |
When the doses are less than maximally efficacious and receptors remain open to be occupied |
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Define surmountable antagonism |
Competitive antagonism: A blocks the effect of B at B's usual threshold and range of effective doses; but an increase in B (shift B's curve to the right) will overcome the effect of A |
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Define Insurmountable antagonism |
Noncompetitive antagonism: A decreases the effectiveness of B and no increase in B's concentration can lead to a situation where maximum efficacy is restored (curve shape changes and efficacy is decreased) |
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Define Therapeutic Index |
LD50/ED50 **Always have this one** |
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Define Margin of Safety |
LD01/ED99 **May not always have this one** |
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What are some advantages (3) of dose-response curves? |
1. Identification of drug properties (intrinsic activity, maximal efficacy, threshold, range of therapeutic and toxic doses, risk-benefit) 2. Comparison of agonists, partial agonists for efficacy and potency 3. Studies of drug interactions (how does an antagonist affect an agonist) |
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What are some pitfalls (3) of the dose-response curve? |
1. Low-dose extrapolations are hard to do 2. Only one response can be determined at a time 3. Toxicity is not necessarily the same as lethality |
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Elimination includes: |
Biotransformation to inactive druge + excretion |
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What are two aspects of cell membranes that affect drug absorption? |
1. Membrane composition 2. Membrane permeability |
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Name 5 ways that drugs cross membranes. What are the 2 most likely methods? |
1. Filtration 2. Diffusion (concentration gradient important) 3. Facilitated diffusion (non-energy requiring carrier) 4. Active transport 5. Phagocytosis ** Filtration and diffusion are most likely** |
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Name some aspects of the drug that contribute to absorption. |
1. Concentration gradient 2. Size (MW, Protein binding) 3. Formulation (vehicle of drug) 4. Lipid-water (o/w) partition coefficient (solubility) 5. Drug ionization (solubility) 6. Protein binding in blood (more protein binding will decrease availability for absorption) |
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What form of ionization is necessary for a drug to diffuse across a membrane? |
Unionized |
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Ionized drugs are considered to be _______ |
Ion trapped |
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If a drug is acidic, then the drug will be unionized when the tissue pH is ________ than the drug's pKa. |
Less |
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If a drug is a weak base, then the drug will be unionized when the tissue pH is ______ than the drug's pKa. |
Greater |
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Pharmacokinetics includes: |
Movement of the drug through the body as a concentration versus time function
Absorption, Distribution, Biotransformation, Excretion |
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Pharmacodynamics includes: |
The mechanism of the drug action especially at the cellular level |