- Active Raynaud's Phenomenon
- Stable disease and medication requirements over the previous two months
- For Secondary Raynaud's Phenomenon subjects, a diagnosis of scleroderma using the
American College of Rheumatology criteria or by the presence of at least 3/5 features
of CREST syndrome
- both sexes
- Uncontrolled hypertension, diabetes mellitus, angina, or using oral nitrates
- Smoking within 3 months or smoking cessation using nicotine products
- Subjects currently taking sildenafil, tadalafil or vardenafil
- Subjects with ulnar arterial occlusive disease as shown by a modified Allen test
- Pregnant or breast feeding or considering pregnancy in next 4 months
- Participation in trial for investigational drug within 30 days