Failure of Vasodilator Drugs in Arteriosclerosis Obliterans

Vasodilator drugs were evaluated at rest (nylidrin, isoxsuprine, and tolazoline) and during exercise (nylidrin, isoxsuprine, and nicotinyl alcohol) in patients with intermittent claudication caused by aortoiliac or femoropopliteal arteriosclerosis obliterans. All drugs were given orally in large doses. Blood flows were measured at rest by plethysmography and during exercise by the disappearance rate of a radioisotope from the gastrocnemius muscle. Nylidrin, isoxsuprine, and tolazoline produced no significant change in resting foot flow; nylidrin increased calf flow at rest in patients with femoropopliteal disease. In 54 exercise tests, there were only 6 patients with improved flow during exercise after nylidrin, isoxsuprine, or nicotinyl alcohol treatment, and even these 6 individuals developed claudication at their usual work load. Since patients with intermittent claudication need an increased muscle flow during exercise and patients with ischemia at rest need an increased skin flow, it is concluded that these drugs are without value when used acutely.