Morphine Sulfate/Placebo for the Treatment of PulmonAry Fibrosis Cough

Idiopathic pulmonary fibrosis (IPF) is a disease of unknown cause that results in scarring of the lungs. Cough is reported by 85% of patients with IPF and can be a distressing symptom with significant physical, social and psychological consequences particularly anxiety and depression. The cause of cough in IPF is poorly understood and there are currently no proven effective therapies. Morphine has long been advocated for the suppression of chronic cough in other conditions. While morphine is frequently used as a palliative agent for breathlessness in IPF, its effects on cough have never been tested. The aim of this study is therefore to explore and compare the effect of low dose morphine, one of the few therapies shown to be effective in some patients with otherwise refractory chronic cough, in patients with IPF, to an inactive substance known as a placebo. To make a fair comparison, patients will be randomly allocated to receiving either morphine or placebo in a blinded fashion. This means neither the doctor nor the patient will know which drug they are receiving, and the drugs will appear the same. However, the trial is designed so that you will receive both morphine and placebo, but at different times (this is called a cross-over study). More specifically, you will be given either morphine or placebo for 14 days at a time. In this study, it is hypothesised that compared with placebo, low dose (5mg) controlled release Morphine sulfate (MST) will reduce the number of coughs recorded during a 24hr period in patients with IPF.