Common Drug Eases Leg Cramping

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People with leg cramps caused by narrowing blood vessels often stop walking because of the pain. In fact, some say they have "shop window disease," because they pretend to gaze into store windows during the embarrassing pauses. But those who take naftidrofuryl -- a drug that relaxes blood vessels -- don't have to pause nearly as often, according to a new review by Belgian researchers.

Their analysis of seven studies involving 1,266 patients with the painful condition, officially called intermittent claudication, revealed that those taking the prescription drug for six months walked about 40 percent farther without pain than those taking a placebo.

What's more, well over half of naftidrofuryl-takers improved their walking distance more than 50 percent, compared with just over a third of people taking the placebo. Naftidrofuryl users walked about 93 more yards on average, "reaching both the butcher and the baker instead of only reaching the butcher," says lead author Tine De Backer, M.D.

"Being able to walk that extra distance and have less pain makes an important, meaningful difference for these patients," said De Backer, a cardiologist at the Heart Centre and at the Heymans Institute of Pharmacology at Ghent University.

De Backer noted that naftidrofuryl only treats the type of leg cramping that is a symptom of intermittent claudication. The drug does not treat the cause of the condition, which is peripheral arterial disease -- hardening and narrowing of the blood vessels typically associated with diabetes, smoking, high blood pressure, a sedentary lifestyle, elevated blood lipids and aging. Peripheral arterial disease affects one in 20 Americans over age 50, according to the National Heart, Lung, and Blood Institute.

People with type 2 diabetes have an especially high risk of peripheral arterial disease and its bedfellow, intermittent claudication.

The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates research in all aspects of health care. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing trials on a topic.

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De Backer and her colleagues focused on naftidrofuryl in their review because it is a long-used agent that has been tested in many more quality studies than other drugs in its class of peripheral vasodilators. The drug is also safe and well tolerated by most people; only about a fifth of patients experience minor stomach problems. It is available in affordable generic versions in most countries.

In this review, patients on the typical naftidrofuryl dose of 200 milligrams three times a day showed increased walking benefits, even when researchers teased out the effects of exercise and smoking. Still, the researchers stress that stopping smoking and gradually increasing exercise, along with eating a healthier diet, are the first line of defense against peripheral arterial disease and resulting intermittent claudication.

Patients with these conditions also tend to have problems with cardiovascular disease (CVD) more generally, putting them at increased risk for stroke, as well as heart attacks, angina and other heart troubles. Because peripheral arterial disease creeps in silently, often without symptoms at first or just manifesting as leg fatigue, many patients underestimate the CVD risk, says intermittent claudication researcher Leslie Katzel, M.D., associate professor of medicine at University of Maryland School of Medicine.

Lipid-lowering treatment with such drugs as statins and niacin, and anti-clotting drugs like aspirin -- in addition to lifestyle modification -- can significantly reduce risk.

So, given review findings, should physicians prescribe naftidrofuryl for intermittent claudication? "Yes," De Backer said, "if patients cannot control their symptoms with the drug treatments they are already on and if they are still in pain after making lifestyle modifications."

However, one question the research doesn't address about naftidrofuryl -- one also raised about competitor drug cilostazol --is whether other drug treatments and lifestyle modifications like increased walking would ease symptoms just as much, while doing more to treat the underlying peripheral artery disease. In that case, adding naftidrofuryl or cilostazol, which only treat symptoms, would be unnecessary, says intermittent claudication expert Katzel.

"Anytime you prescribe a medication such as naftidrofuryl, you are adding it to already existing therapies, so the question is how much is the additional benefit," he said. "To find that out, you would need to do a walking program plus placebo versus a walking program plus the drug."

Still, the biggest problem with intermittent claudication, Katzel, said is often that those who have it tend to reduce walking because of the pain. If naftidrofuryl helps them walk more, so much the better, he said.

The Cochrane review disclosed that co-author Philippe Lehert has done statistical work for several pharmaceutical companies, including Merck, which holds the marketing authorization for naftidrofuryl.

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