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35 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is pharmacology? |
How drugs interact with the body; act on a site to trigger effects |
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What is a drug? |
What is a drug? |
Any compound that affects living processeswhat |
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What is drug safety? |
Balancing the therapeutic effects of drugs with the costs |
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What is pharmacokinetics? |
What the body does to the drug |
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What are drug-drug interactions? |
These can occur at a kinetic or dynamic level, some block and others activate. At a kinetic level, they may compete at the same level and induce rnYmes |
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Why do we use a semi-log scaled sigmoid curve for dose-response? |
Allows us to look over a large range of concentrations |
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What is potency? |
Potency refers to the dose range if which the drug is active in increasing response for increasing dose |
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How is relative potency determined? |
A ratio of doses that produce the same effect to see which is more potent |
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Which is more important, relative therapeutic efficacy or relative potency? |
Therapeutic efficacy- you can always give more of the drug to elicit the same effect of low potency |
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What is Quantal/population dose-response relationship? |
Find the minimal dose needed to elicit the specific effect, across a group of people. This response can mean many different things, e.g. inter-individual variability exists so we can see what is needed for a population instead of an indictable basis. How the minimal dose required to elicit a specific effect varies across a group of people |
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What is ED50? |
The dose that produces a desired effect in 50% of the population At either end of this scale there are hypersensitive people (could be more at risk for toxic effect) and hyposensitive people |
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What is the Therapeutic Index/Window? |
The TI is the gap between the therapeutic effect and the toxic side effect curve - the larger the TI, the safer the drug |
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What is L-Dopa used for? |
Parkinson’s Disease Post Mortem examination of patient’s brains showed dopamine deficiency. Dopamine does not enter brain easily if injected/ingested due to the BBB; L-Dopa is used to synthesize dopamine in the brain by inserting a precursor. The result was temporary symptom relief but long-term usage became problematic due to peripheral toxic effects; an inhibitor in the periphery increased the safety of the drug. Diagnosis: if patients respond to the drug it is usually indicative of Parkinson’s |
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What is Response? |
Response is an all-or-none response, but can be a predefined magnitude of a graded response |
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What is the goal of a Quantal Dose-Response relationship? |
To generalize a result to a population beyond the individual graded dose-response curve |
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What is a drug receptor? |
A drug receptor is any biological component that interacts with with a drug molecule and that leads to an effect |
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Why is drug binding usually reversible? |
Mutual adaptation of specific chemical groups to allow reversible binding in 3D space |
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What is involved in Structure-activity relationships (SAR)? |
Small changes in chemical structure can lead to big changes in activity of compound to interact with the target site e.g. ACh receptors- methyl acetyl choline will only interact with one receptor found in the heart to slow it down, will not affect skeletal muscle at the usual dose. |
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What is an antagonist? |
An antagonist is a drug which binds with relatively higher affinity to the target sire & prevents the endogenous ligand acting at the site. |
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Examples of Drug Receptors |
Intercellular targets Ligand-gated membrane receptors Enzymes & their substrates/inhibitors Soluble receptors and antibodies targeting mediators Active transporters Drugs/Toxins |
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Describe the Occupation Theory of Drug Action |
Drugs only act as long as they occupy the receptor |
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What is the law of mass action? |
The velocity of a reaction depends on the concentrations of the reactants; when a chemical reaction reaches equilibrium, the concentrations of the chemicals involved bear a constant relationship to each other, which is described by the equilibrium constant. |
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What is the Equilibrium constant for receptor? |
KD = Koff/Kon |
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What determines Emax? |
The number of receptors in the tissue- receptor density |
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What is efficacy? |
Tendency, one bound, to activate the receptor |
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Relative efficacy |
The ratio of the receptor occupancy at which 2 activators produce the same response |
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What are effectors? |
Molecules that translate the DR interaction into a change in cellular activity |
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Agonist |
A drug that causes an effect as a result of a direct alteration of receptor function (receptor stimulant) - achieves max receptor efficacy level |
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Antagonist |
A drug that binds to a receptor without activating it. Instead, it blocks the action of the agonist (0 receptor efficacy level) |
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Partial agonist/antagonist |
A drug that cannot trigger a max response from a tissue when 100% receptors are occupied (low-to-moderate receptor efficacy level) |
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Competitive antagonist |
Will bind to the same site as the agonist and block it’s effects e.g. atropine binds to same site as ACh, this block is reversible. Agonist potency reduced |
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What is a non-competitive antagonist? |
These drugs don’t occupy the same site as the agonist (occupy alosteric instead of orthosteric site); irreversible. Reduce agonist efficacy. |
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What is an inverse agonist? |
Agents which bind to the same site as the agonist but exert opposite pharmacological effects Show selectivity for the “inactive” state of receptors with “basal activity” |
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What does potentiation do? |
Enhances response of another drug |
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Tolerance and tachyphlaxis |
Tolerance- Loss of response to drug overtime (hours-days) Tachyphylaxis - raid loss of response to drug e.g. drug acts to release an endogenous transmitter and available pool is depleted |
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