Antithrombotic Therapy in Peripheral Arterial Occlusive Disease: Pentoxifylline
AS-013, a PGE1 prodrug, was evaluated in a randomized clinical trial of 80 patients (level II) with claudication, and was associated with an increase of 35 m in maximal walking distance after 8 weeks of treatment, compared with a slight decrease in placebo-treated controls. This difference was statistically significant (p < 0.01), although the clinical significance of the increase is somewhat marginal. Two significant complications occurred in patients receiving AS-013: one episode of atrial fibrillation and one episode of sustained hypotension. In current practice, the lack of available oral forms of prostaglandins, their adverse hemodynamic effects, and lack of demonstrated superiority over conventional agents such as aspirin, have resulted in a limited use of these compounds.
Pentoxifylline, a methylxanthine derivative, is the only hemorheologic agent currently approved by the Food and Drug Administration for treatment of intermittent claudication. In patients with peripheral arterial disease, pentoxifylline has been reported to improve abnormal erythrocyte deformability, reduce blood viscosity, and decrease platelet reactivity and plasma hypercoagulability. Thus, pentoxifylline is a weak antithrombotic agent and its beneficial effects may stem from other pharmacologic properties. A number of clinical trials (levels I and II) have evaluated pentoxifylline. Reading here canadian healthcare mall Many concluded that pentoxifylline was significantly more effective than placebo in improving treadmill walking distances, but six trials could not demonstrate consistent benefit. In most trials, patients treated with placebo also had significant improvement and this tended to obscure benefits attributable to active drug treatment. A critical review of these trials concluded that the actual improvement in walking distance attributable to pentoxifylline is often unpredictable, may not be clinically important compared to the effects of placebo, and does not justify the added expense for most patients. The drug may have a role in a few patients with markedly reduced walking distances who are unresponsive to or cannot engage in exercise therapy; for such patients, even a small increase in claudication walking distance may allow activities that were previously impossible.