Effects of Vardenafil on Clinical Symptoms and Peripheral Blood Flow in Patients With Raynaud's Syndrome

Inclusion Criteria: * raynaud-syndrome (primary or secondary) \> 1 year duration * age ≥ 18 years; ≤ 80 years * informed consent * a negative pregnancy test in women of child-bearing age Exclusion Criteria: * any unstable organic, psychiatric or addictive disease, which - in the opinion of the investigators - might result in an unsuccessful / unreliable participation or premature termination of the trial * known contraindications against PDE 5-inhibitors (such as intolerance, therapy with nitrates or inhibitors of CYP3A4, etc.) * extensive necrosis of the finger tips * pigmentary retinopathy * verification as a HbsAg or hepatitis C carrier * unstable angina * heart failure (NYHA III or IV) * valve defects of higher degree (particularly aortic stenosis and hypertrophic obstructive cardiomyopathy) * myocardial infarction, stroke or life-threatening cardiac arrhythmias within the last 6 months * uncontrolled atrial fibrillation / -flutter with a heart rate \> 100 bpm * prolonged QTc-interval (\> 450 msec) * congenital long-QT-syndrome * hypokalemia * severe acute or chronic liver disease, which might lead to priapism (sickle cell anemia, leucemia) * hemophilia * active peptic ulcers * arterial hypotension (systolic blood pressure at rest \<90 mmHg) or * arterial hypertension(systolic blood pressure at rest \>170 mmHg or diastolic blood pressure at rest \>110 mmHg) * malignancy within the last 5 years (except squamous or basal cell skin cancer) * patients with injuries of the spinal cord or central nervous system * patients with severe chronic kidney disease (creatinin clearance \< 30 ml) * patients with mild to severe liver disease (Child-Pugh A-C) * Age below 18 or above 80 * prohibited concomitant medication during the study: * nitrates or other NO-donators (including amylnitrit) * anticoagulative drugs except inhibitors of thrombocyte function * androgens (such as testosterone) or anti-androgens * strong inhibitors of cytochrome P4503A4: * very potent HIV-Protease-inhibitors (ritonavir, indinavir) * anti-mycotic like itraconazole and ketoconazole (topical applications are allowed) * erythromycin * grapefruit-juice or products containing grapefruit-juice * other study medications (including placebo) up to 30 days before study inclusion * therapy of erectile dysfunction(including sildenafil, sublingual apomorphin, MUSE®, intracavernous injections or vacuum pumps) or other therapies of erectile dysfunction within 4 weeks and during the trial period * nebivolol * alpha-blockers * Calcium antagonists * medications prolonging the QT-interval * abnormal lab tests like: * serum-creatinine \> 3 mg/dl at visit 1 * GOT and GPT \> 3 x reference limit set * diabetes mellitus with a HbA1c \> 9% * patients who are not willing to disclaim a therapy of their erectile dysfunction with vacuum pumps, intravenous injections, sildenafil or other therapies during the trial * severe migraine (more than once a moth during the last 6 months) * intolerance to the study medication * patients who are not able to understand the information and informed consent due to a mental disorder or linguistic barriers * persons who are living in a institution directly under federal government control due to a court order * patients who refuse to renounce drinking grapefruit juice during the trial * women who are pregnant or lactating * women who are not protected from a pregnancy (intake of oral contraceptives alone in insufficient; highly effective methods of birth control have to be used with a failure rate \<1%; barriers: implants, intrauterine-devices (IUD´s),diaphragm, condoms, abstinence, partner is vasectomized, spermicides) * patients who participated in other interventional studies within 30 days of study inclusion