| Roflumilast | Placebo | |
| Body as a whole (flu syndrome, abdominal pain, malaise, back pain) | 17 (45) | 10 (26) |
| Digestive system (diarrhea, nausea, abnormal stool, vomiting, dyspepsia) | 17 (45) | 4 (10) |
| Nervous system (headache, dizziness) | 17 (45) | 2 (5) |
| Respiratory system (increased cough, dyspnoea, upper respiratory tract infection, rhinitis, increased sputum production) | 16 (42) | 15 (39) |
| Cardiovascular system (ECG abnormal, chest pain, palpitation, thrombophlebitis) | 4 (11) | 1 (3) |
Adverse events with incidence ⩾1% are listed.