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17 Cards in this Set
- Front
- Back
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What is addition when talking about drug effects? |
Addition is when the combined effect of two drugs is the same as the sum of the individual effects of the two drugs. |
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What is potentiation when talking about drug effects? |
Potentiation is when the combined effect of two drugs is larger than as the sum of the individual effects of the two drugs. |
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What is antagonism when talking about drug effects? |
Antagonism is when the combined effect of two drugs is smaller than as the sum of the individual effects of the two drugs. |
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What types of antagonism exist?
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Reversible competitive antagonism Irreversible competitive antagonism Allosteric antagonism Antagonism by inhibition of signal transduction Functional antagonism Pharmacokinetic antagonism Chemical antagonism |
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What is reversible competitive antagonism? |
Reversible competitive antagonism is when the antagonist binds reversibly to the same binding site on the receptor as the agonist or endogenous ligand. |
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What is irreversible competitive antagonism? |
Irreversible competitive antagonism is when the antagonist binds irreversibly to the same binding site on the receptor as the agonist or endogenous ligand. |
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What is allosteric antagonism? |
Allosteric antagonism is when the antagonist binds to an allosteric binding site on the receptor, decreasing the effect of the agonist |
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What is antagonism by inhibition of signal transduction?
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Antagonism by inhibiton of signal transduction is when the antagonist inhibits the signal transduction pathway of the agonist |
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What is functional antagonism?
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Functional antagonism is when the antagonist exert effects on the cell which are opposite effects of the agonist |
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What is pharmacokinetic antagonism? |
Pharmacokinetic antagonism is when the antagonist decreases the absorption or increases the elimination of the agonist |
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What is chemical antagonism? |
Chemical antagonism is when the antagonist chemically binds to the agonist and inactivates it |
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What is the margin of safety/therapeutic index and how is it calculated? |
The margin of safety or therapeutic index is the ratio of TD50/ED50. It tells us how safe the drug is at the therapeutic dose |
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What do we mean when we say that reversible competitive antagonism is surmountable? |
It means that the agonist may still reach the full effect (100%) after the antagonist is applied, as long as a large enough dose of agonist is applied. |
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How can partial agonists act as antagonists? |
The endogenous ligand is often a full agonist. If we add an exogenous partial agonist to the mix will the partial agonist bind to some of the receptors instead of the endogenous full agonist. This results in an overall reduction in "agonist" activity. |
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Mention some examples of chemical antagonism. |
Protamine and heparin, or sugamamdex and succinylcholine. |
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Name some drugs which have a small margin of safety/therapeutic index |
Lithium, theophylline, digoxin |
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Name some drugs which have a large margin of safety/therapeutic index |
Glucocorticoids, penicillin, antihistamines |
