German researchers have discovered yet another use for Viagra (sildenafil), they say it relieves the symptoms and improves the circulation of patients with Raynaud's phenomenon.
Raynaud's phenomenon is characterized by spasms in the small blood vessels of the hands and feet in response to cold or stress, and results in poor circulation and pain.
In extreme cases the disorder can also lead to ulceration or tissue death in the toes and fingers.
Until now the condition has been difficult to treat as it does not generally respond to conventional therapy.
The investigators report that in patients with ulcers on their fingers or toes, the treatment leads to healing.
Originally Viagra was developed to treat male erectile dysfunction, and is a phosphodiesterase (PDE)-5 inhibitor that affects very small blood vessels, but studies have shown it improves circulation in other conditions, such as coronary artery disease.
In their research Dr. Roland Fries and colleagues, from Gotthard-Schettler-Klinik in Bad Schonborn, Germany, monitored 18 patients with severe Raynaud's phenomenon that had failed to respond to at least two other drugs.
They were randomly assigned 50 mg of Viagra twice daily for 4 weeks or a placebo for 4 weeks, followed by a "washout" period of 1 week with no treatment; then the groups switched treatments.
According to their report, Viagra reduced the frequency of Raynaud attacks (35 versus 52), attack duration (581 versus 1046 minutes) and Raynaud's phenomenon scores (2.2 versus 3.0).
In the six patients who had chronic toe or finger ulcerations, the sores healed significantly during active treatment, disappearing completely in two patients.
However, the sores reappeared or progressed again after treatment with Viagra was stopped.
The team say that treatment with this class of drugs promises a new approach for patients with microcirculatory disorders.
The report is published in the November issue of Circulation, a Journal of the American Heart Association.