| Study characteristics |
| Methods |
Double blind randomised placebo controlled parallel trial |
| Participants |
14‐25 year old females with primary dysmenorrhoea |
| Interventions |
Nifedipine 5mg 8 hourly as needed for up to 3 days (n = 22) versus placebo (n = 20) |
| Outcomes |
Relief score (ability to relieve symptoms), severity score (degree to which dysmenorrhoea interfered with activities), need for additional analgesics, side effects |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Not stated in methods |
| Allocation concealment (selection bias) |
Unclear risk |
Not described |
| Blinding of participants and personnel (performance bias)
All outcomes |
Low risk |
Stated used double‐blind technique |
| Blinding of outcome assessment (detection bias)
All outcomes |
Unclear risk |
Stated used double‐blind but not clearly described |
| Incomplete outcome data (attrition bias)
All outcomes |
High risk |
8 out of total 50 patients dropped out of trial without stating reasons |
| Selective reporting (reporting bias) |
Low risk |
All remaining 42 participants' data included |
| Other bias |
Low risk |
Nil identified |
