A cramp-like pain that occurs in the legs on walking. It may cause the sufferer to limp or, if severe, stop him or her from walking. The usual cause is narrowing or blockage of the arteries in the legs due to ATHEROSCLEROSIS: smoking is a contributory factor. Intermittent claudication occurs when a person has to stop every so often to let the pain – caused by the build-up of waste products in the muscles – to subside. The condition may be improved by exercise, for example, for an hour a day (resting when the pain starts). Pentoxifylline, a vasodilator, may be prescribed, as may CALCIUM-CHANNEL BLOCKING DRUGS. Patients must avoid all tobacco products.