| Methods |
RCT |
| Participants |
82 university students and staff, mean age 24 years (range 18 to 46), 62% men, 'common cold centre', university department, UK, cough associated with URTI |
| Interventions |
Antitussive: codeine phosphate 50 mg as a single dose |
| Outcomes |
5‐point subjective rating scale, cough sound pressure levels, cough frequency |
| Notes |
No data on adverse effects reported |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Not reported |
| Allocation concealment (selection bias) |
Unclear risk |
Not reported |
| Blinding (performance bias and detection bias)
All outcomes |
Low risk |
Patients and providers blinded; outcome assessor blinding not reported |
| Incomplete outcome data (attrition bias)
All outcomes |
Unclear risk |
Follow‐up not reported |
| Selective reporting (reporting bias) |
Unclear risk |
Not reported |
| Other bias |
Unclear risk |
No power calculation reported |
