PDE4A and chronic obstructive pulmonary disease: Roflumilast (3-cyclo-propylmethoxy-4-difluoromethoxy-N-[3,5-dichloropyrid-4-yl]-benzamide) is the only PDE4 inhibitorapprovedby the US FDA and the European Medicines Agency (EMA) as an oral,once-daily tablet for the treatment of severe COPD associated withchronic bronchitis.4 In particular, itimproves airway remodeling, ventilation, and mucociliary functions,reduces oxygen free radical release, inhibits pulmonary fibrosis,and shows anti-inflammatory effects.