Gefapixant is primarily used in the treatment of chronic cough, particularly in cases where the cough is refractory or unexplained. It works by selectively blocking the P2X3 receptor, which is involved in the sensitization of cough reflexes. This mechanism helps reduce the frequency and intensity of coughing episodes, providing relief to patients who have not responded to other treatments. It is especially beneficial for individuals with conditions like chronic idiopathic cough or cough associated with underlying respiratory diseases. Clinical trials have demonstrated its efficacy in improving quality of life by significantly lowering cough frequency.