Non-Competitive Antagonist

A drug that inhibits agonist action by binding to an allosteric site on the receptor or at a point downstream in the signaling cascade, reducing the maximal response achievable by the agonist regardless of agonist concentration. The dose-response curve shows a depressed maximum without a rightward shift. Non-competitive antagonism can be reversible or irreversible depending on binding kinetics.

Ejemplos

• Ketamine: non-competitive NMDA receptor antagonist (channel blocker)
• Verapamil: non-competitive antagonist at L-type calcium channels in the context of beta-agonist cardiac stimulation
• Picrotoxin: non-competitive antagonist at GABA-A receptor chloride channel