Daxas contains the active substance roflumilast, which is an anti-inflammatory phosphodiesterase-4 inhibitor. Roflumilast reduces the activity of phosphodiesterase-4, a protein that is found naturally in the cells of the body. When the activity of this protein is reduced, inflammation in the lungs decreases. This helps stop the narrowing of the airways that occurs in chronic obstructive pulmonary disease (COPD). Therefore Daxas relieves respiratory problems. Daxas is used for the maintenance treatment of severe COPD in adults who have had frequent worsening of their COPD symptoms in the past (so-called exacerbations) and who have chronic bronchitis. COPD is a chronic disease of the lungs that results in narrowing of the airways (obstruction) and swelling and irritation of the walls of the small airways of the lungs (inflammation). This leads to symptoms, such as coughing, wheezing, chest tightness, or shortness of breath. Daxas must be used together with bronchodilators.