| Adverse event# | Ivacaftor¶ | Placebo+ |
| Headache | 26 (24) | 17 (16) |
| Oropharyngeal pain | 24 (22) | 19 (18) |
| Upper respiratory tract infection | 24 (22) | 14 (14) |
| Nasal congestion | 22 (20) | 16 (15) |
| Abdominal pain | 17 (16) | 13 (13) |
| Nasopharyngitis | 16 (15) | 12 (12) |
| Diarrohea | 14 (13) | 10 (10) |
| Rash | 14 (13) | 7 (7) |
| Nausea | 13 (12) | 11 (11) |
| Dizziness | 10 (9) | 1 (1) |
Data are presented as n (%). No significant signals were identified through to week 48. #: occurring more commonly (≥8%) in ivacaftor-treated subjects; ¶: n=109; +: n=104.