| Study characteristics |
| Methods |
Study design: randomized double‐blind placebo‐controlled cross‐over trial
Method of randomization: not stated
Concealment of allocation: not stated
Exclusions post randomization: none
Losses to follow‐up: none |
| Participants |
Country: Denmark
Setting: not stated; winter season
No.: 10/10 primary RP
Age: median 44 years (range 27 to 71 years)
Sex: females 8; males 2
Inclusion criteria: primary RP; screened for underlying disease
Exclusion criteria: secondary RP according to described criteria; hypertension BP > 150/90 |
| Interventions |
Treatment: captopril 25 mg 3 times daily
Control: placebo 1 three times daily
Duration: 2 × 6 weeks
Washout period: none |
| Outcomes |
Number of daily attacks
Accompanying numbness or pain
Improvement on 3‐point scale: improved, unchanged, worse
Adverse events |
| Notes |
No power calculation
Support: pharmaceutical company |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
No description of sequence generation methods |
| Allocation concealment (selection bias) |
Unclear risk |
No description of allocation concealment methods |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
Study described as double‐blind but no further explanation of blinding methods |
| Blinding of outcome assessment (detection bias)
All outcomes |
Unclear risk |
No indication of blinding of outcome assessors |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
All 10 participants completed the study |
| Selective reporting (reporting bias) |
Low risk |
All study outcomes reported |
| Other bias |
Unclear risk |
Cross‐over study; study authors did not evaluate carry‐over of treatment effects and therefore could be of concern |
