Raynaud’s Phenomenon Improves with a Modified Viagra Drug

Raynaud's phenomenon occurs when the small blood vessels in the hands and feet overreact to cold temperatures. The fingers or toes become pale, followed by blueness (cyanosis), redness, or both, accompanied by pain and tingling. The small vessel spasms can lead to ulceration of the fingers and even gangrene. Raynaud's disease, also called primary Raynaud's, occurs in people without an obvious medical cause for the condition. Secondary Raynaud's phenomenon is seen in patients with autoimmune diseases such as scleroderma, systemic lupus erythematosus, and rheumatoid arthritis.

Because of the spasm of arteries that are often thickened, researchers theorized that a drug like Viagra (sildenafil, taken for erectile dysfunction in men) might be used to treat the condition. A study conducted at the University of Manchester in UK, and published in the Journal Arthritis and Rheumatism, suggests this may be so.

This double-blind, placebo-controlled study enrolled 57 patients with Raynaud's phenomenon secondary to cutaneous scleroderma. To be eligible, patients had to have a frequency of at least seven attacks a week on five or more days. They were randomized to take modified-release sildenafil (100 mg daily for three days followed by 200 mg daily for 25 days) or a matching placebo. Patients recorded the number of Raynaud's attacks per week, the duration of attacks, a pain score, and results from a device measuring arterial pressure in the fingers.

The average number of attacks per week was reduced over the 28 days by a greater amount in the sildenafil patients than in those taking the placebo (-44% versus -18%). The average number of attacks per week improved from 25 to 19.3 after placebo treatment and from 30.5 to 18.7 with sildenafil treatment. None of the other measures recorded showed significant changes between the improvements in both groups in this small study.

So here’s another example of a drug taken for one condition (erectile dysfunction) proving potentially useful for treating another.  (Note this was a modified-release form of sildenafil, not regular Viagra.) It’s likely, however, that the main benefit of this study will be its use as a signpost, pointing to a class of drugs to be searched for more potent (and patentable?) candidates.