Pharmacology
Antagonism
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Get access- The effect of one drug is reduced or blocked by another
- Pharmacokinetic antagonism
- One drug affects the absorption, metabolism or excretion of another
- Eg. enzyme inducers reduce the levels of warfarin
- Competitive antagonism
- Both drugs bind to the same receptor
- Reversible: increasing the concentration of the agonist can overcome the antagonist
Irreversible: the antagonist dissociates slowly (or doesn’t) and so cannot be overcome by increasing the agonist
- Non-competitive antagonism
- Antagonist works downstream of the receptor
- Physiological antagonism
- Two drugs have opposing actions on the body and so cancel each other out