Pentoxifylline: a new drug for the treatment of intermittent claudication. Mechanism of action, pharmacokinetics, clinical efficacy and adverse effects.

During the past decade, the effectiveness of peripheral vasodilator drugs in the treatment of chronic occlusive arterial disease has been questioned. Pentoxifylline is a hemorheologic agent with primary actions that include increasing erythrocyte flexibility, reducing blood viscosity and increasing microcirculatory flow and tissue perfusion. The result is improved supply of oxygen to ischemic muscles of the limbs. In several double-blind studies, pentoxifylline increased walking distance of patients with intermittent claudication in comparison to placebo or vasodilators. Like other methylxanthines, pentoxifylline is well absorbed in the gastrointestinal tract, almost completely metabolized in the body and excreted in the urine. The most significant difference in its pharmacokinetics is that, unlike other methylxanthines, it is bound to the erythrocytic membrane where it is initially metabolized. Although pentoxifylline has been shown to be effective in the treatment of intermittent claudication, additional research is needed to determine its use as adjunctive therapy in patients with concurrent coronary or cerebrovascular disease.