| Study characteristics |
| Methods |
Randomised controlled trial |
| Participants |
Women aged 15 to 35 years with primary dysmenorrhoea (n = 24) |
| Interventions |
Nifedipine 10 mg capsules (n = 19) versus placebo (n = 5) |
| Outcomes |
Relief of pain, if substance was better than previous analgesic, if would use substance monthly, amount of relief, dosage schedule needed if more than one pill used, side effects |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Probably done but uncertain; "randomised through hospital pharmacy". Very uneven numbers in each group: nifedipine = 19; placebo = 5. |
| Allocation concealment (selection bias) |
Unclear risk |
Not described |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
Placebo capsules were identical‐looking. Not clearly stated |
| Blinding of outcome assessment (detection bias)
All outcomes |
Unclear risk |
Not clearly stated |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
All participants accounted for |
| Selective reporting (reporting bias) |
Unclear risk |
Participants recorded reaction to the medications as they occurred but these and side effects were discussed with investigator at follow‐up visit |
| Other bias |
Low risk |
Nil identified |
