Wigley 1987.

Methods	Randomized double‐blind placebo‐controlled trial Cross‐over design
Participants	N = 25 patients ‐ 21 female, 4 male Mean age 39 ± 2.6 years, range 22 to 65 19 of Caucasian descent Average disease duration 4.75 ± 0.8 years 10 with primary Raynaud's phenomenon, 15 with Raynaud's phenomenon secondary to connective tissue disorder No dropouts during cross‐over phase, 2 dropouts during parallel phase
Interventions	Participants randomly assigned to receive nicardipine or placebo for first 2 weeks followed by a second 2‐week period with agent not taken Continuation of agent from the second treatment period for an additional 4 weeks in a parallel design Total study duration 4 weeks
Outcomes	Participant diary used to record frequency and severity Finger systolic pressure and venous sampling performed Beta‐thromboglobulin and platelet factor 4 measured
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 study
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"Subjects kept a daily diary of the frequency and severity of attacks."
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts during cross‐over period of the study
Selective reporting (reporting bias)	Low risk	None detected
Other bias	Unclear risk	Evidence insufficient for judgement of risk