Gjorup 1986a.

Methods	Double‐blind placebo‐controlled randomized trial Cross‐over design
Participants	N = 19 patients ‐ 15 female, 4 male Median age 40 years, range 22 to 60 All with typical Raynaud's phenomenon Selected from files of general practitioners in hospital area Study completed by all patients
Interventions	3‐Week periods of active and placebo treatment Participants assigned to receive nisoldipine or placebo during first period Study conducted during March and April Total study duration 6 weeks
Outcomes	Participant diary used to record daily number of attacks, grade of the most severe attack (on a scale from 1 to 10), whether the day had been better or worse than expected, and overall evaluation of preferred treatment Side effects also recorded
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Evidence insufficient for judgement of risk
Allocation concealment (selection bias)	Unclear risk	Evidence insufficient for judgement of risk
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"Double‐blind cross‐over study"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"Patients recorded number of attacks, severity, and efficacy."
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up
Selective reporting (reporting bias)	Low risk	None detected
Other bias	Unclear risk	No mention of a washout period between cross‐over phases