Quick Overview

Gefapixant is a selective antagonist of the P2X3 receptor. Gefapixant also has activity against the P2X2/3 receptor subtype. P2X3 receptors are ATP-gated ion channels found on sensory C fibers of the vagus nerve in the airways. C fibers are activated in response to inflammation or chemical irritants. ATP is released from airway mucosal cells under conditions of inflammation. Binding of extracellular ATP to P2X3 receptors is sensed as a damage signal by C fibers. Activation of C fibers, which is sensed by the patient as an urge to cough, initiates a cough reflex. Blockade of ATP signaling through P2X3 receptors reduces excessive sensory-nerve activation and excessive cough induced by extracellular ATP