GSK2339345 Hypertussive Challenge Study

Inclusion Criteria * Chronic Idiopathic Cough patients according to the criteria listed below, determined by a responsible and experienced physician, based on a medical evaluation: Idiopathic cough defined as chronic cough resistant to treatment targeted at potential triggers. Chronic cough defined as cough lasting for more than 8 weeks. * A patient with a clinical abnormality or laboratory parameters outside the reference range for the population being studied may be included only if the Investigator and the GSK Medical Monitor agree that the finding is unlikely to introduce additional risk factors and will not interfere with the study procedures. * Male/females aged \>=18 years old, at the time of signing the informed consent. * Non-smoker for at least 6 months with a cumulative history of \<= 10 pack years. Pack years = (No. of cigarettes smoked/day/20) x (No. of years smoked). * Body weight \>= 50 kilograms. * A female subject is eligible to participate if she is of; Non-childbearing potential defined as pre-menopausal females with a documented tubal ligation or hysterectomy \[for this definition, "documented" refers to the outcome of the investigator's/designee's review of the subject's medical history for study eligibility, as obtained via a verbal interview with the subject or from the subject's medical records\]; or postmenopausal defined as 12 months of spontaneous amenorrhea \[in questionable cases a blood sample with simultaneous follicle stimulating hormone \> 40…