Tadalafil for the Treatment of Raynaud's

Inclusion Criteria: * active Raynaud's Phenomenon * stable disease and medication requirements over the previous 2 months * subjects willing and able to participate in study assessments * ability to understand and sign informed consent * ages 18 to 65, both sexes * a diagnosis of diffuse or limited cutaneous sclerosis, MCTD using the American College Rheumatology criteria Exclusion Criteria: * uncontrolled HTN, DM, unstable disease, angina or using oral nitrates * smoking, active alcoholism, drug abuse within 5 years * abnormal renal function * ulnar arterial occlusive disease as shown by a positive Allen Test * Pregnant or breast feeding or considering preg. in next 4 months * past or present major psych. illness * allergy or sensitivity to tadalafil * subject unable to understand protocol or give informed consent * part. in another study trial within 30 days * taking sildenafil