Leppert 1989.

Methods	Single‐blind dose response study Cross‐over design
Participants	10 female patients Mean age 43 ± 7 years All with disabling primary Raynaud's phenomenon All with finger cytosolic pressure at 10°C below 50% of the value at 30°C All with severe Raynaud's phenomenon for a mean period of 12 ± 6 years 0 dropouts
Interventions	Total duration of treatment 9 weeks After an initial placebo run‐in period of 3 weeks, participants given isradipine capsules at a dose of 1.25 mg twice daily for 3 weeks, followed by 2.5 mg for a further 3 weeks No vasoactive compounds other than isradipine taken
Outcomes	Finger systolic pressure measured At the end of each period, finger systolic blood pressure measured and participants questioned regarding side effects Participant assessment of effectiveness of therapy on a 0 to 100 mm visual analogue scale
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	Unclear risk	Single‐blind study; participants unaware of their treatment arm
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Subjective participant assessment of outcomes
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts
Selective reporting (reporting bias)	Unclear risk	None detected
Other bias	Unclear risk	Evidence insufficient for judgement of risk