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In Brief: Viagra may help with cold feet and hands

In Brief

Viagra may help with cold feet and hands

The erectile dysfunction (ED) drugs all work in pretty much the same way. They relax constricted blood vessels in the penis by inhibiting an enzyme (phosphodiesterase type 5) crucial to the complicated business of maintaining proper blood vessel “tone.” The spongy erectile tissue in the penis swells when blood flows in through dilated (opened) blood vessels. The erection is maintained by swollen tissue pressing on veins so the blood can’t escape.

People with Raynaud’s syndrome also have a problem with uptight blood vessels: The small blood vessels that supply their feet and hands go into spasm, usually in response to cold or occasionally stress. Because blood can’t get through, their fingers and sometimes toes become numb and painful. In severe cases, which usually involve connective tissue disease, Raynaud’s can result in the death of tissue and complications like gangrene.

Could the ED drugs be used to relax blood vessels in the hands and feet of Raynaud’s sufferers? Findings from a couple of recent studies suggest they might.

In one study, 18 people with Raynaud’s were randomly assigned to take either a placebo pill or 50 mg of sildenafil (Viagra) twice a day for four weeks. After a one-week “washout” period, those taking the placebo switched to sildenafil, and vice versa.

The volunteers’ symptoms improved when they were taking sildenafil but not when they were taking the placebo. Some tests showed why that might be so: The drug quadrupled blood flow through capillaries. These findings were reported in the journal Circulation in late 2005.

In another study, 40 people with Raynaud’s took 10 mg of a different ED drug, vardenafil (Levitra), twice a day for two weeks. About 70% said their Raynaud’s symptoms improved, and tests showed a big improvement in the blood flow in their fingers. These results were reported in the Archives of Internal Medicine in January 2006.

The studies were small. Many of the participants had secondary Raynaud’s, when the condition is the result of another health problem, such as lupus or rheumatoid arthritis. And Raynaud’s sufferers do have alternatives. The standard advice is to stay out of the cold as much as possible. Calcium-channel blockers or other medications that relax blood vessels can be prescribed.

But come winter, maybe the ED drugs will be something else for Raynaud’s sufferers to try.

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Last updated:	August 21, 2006