List of products in the National Drug Code with proprietary name . This medication is used to improve the symptoms of a certain blood flow problem in the legs/arms (intermittent claudication due to occlusive artery disease). Pentoxifylline can decrease the muscle aching/pain/cramps during exercise, including walking, that occur with intermittent claudication. Pentoxifylline belongs to a class of drugs known as hemorrheologic agents. It works by helping blood flow more easily through narrowed arteries. This increases the amount of oxygen that can be delivered by the blood when the muscles need more (such as during exercise) thereby increasing walking distance and duration.