Competitive and non-competitive antagonism

 

Feature	Competitive antagonism	Non-competitive antagonism (equilibrium type)	Non-competitive antagonism (Non-equilibrium)
Site of receptor binding	Same as that of agonist (orthosteric)	Different from that of agonist (Allosteric)	Same as that of agonist (orthosteric)
Reversibility of binding	Reversible	Reversible	Irreversible (strong covalent bonds)
Dose response curve at increasing concentration of antagonist	Rightward shift	Flattening	Flattening
Maximal response	Reached with increase in concentration of agonist (surmountable)	Not reached with increase in concentration of agonist (Unsurmountable)	Not reached with increase in concentration of agonist (Unsurmountable)
Duration of action	As long as antagonist is above the threshold concentration	As long as antagonist is above the threshold concentration	Action persists even if plasma is cleared of the antagonist. Action returns after fresh receptors are synthesized which bind the agonist