Pentoxifylline Improves Pulmonary Gas Exchange

Abstract

Pentoxifylline is a xanthine derivative with hemorrheologic and vascular properties that may improve gas exchange in patients with chronic obstructive pulmonary disease (COPD). We tested this hypothesis in 12 patients with COPD (mean FEV1 = 40 percent predicted; mean DCO, 8.6 ml/min/mm Hg) randomly divided into a treatment and control group and six healthy volunteers. Following establishment of baseline DCO and maximum expiratory flow volume (MEFV) curve values, each subject in the treatment and healthy groups took 400 mg of pentoxifylline three times a day for 12 weeks. Weekly DCO and MEFV curves were measured before treadmill exercise in both COPD groups and before and after exercise in the healthy group. The MEFV curve parameters from the final three weeks of therapy did not differ significantly from baseline values. During this time, however, the treatment COPD group's resting DCO rose by 8.2 +/- 2.4 percent over baseline level (p less than 0.01). Treadmill walk time increased from 17.7 +/- 2.9 minutes to 23.2 +/- 2.9 minutes (p less than 0.02). This was accompanied by improved exercise oxygen saturation measured by oximetry (SoxiO2). Premedication SoxiO2 fell from 92.8 +/- 1.2 percent to 88.6 +/- 2.5 percent during exercise, and from 94.4 +/- 1.1 percent to only 91.8 +/- 1.0 percent after 12 weeks of medication (p less than 0.05). No such improvement was noted in the control COPD group. Although the healthy group's resting SoxiO2 and DCO did not change during treatment, their exercise DCO increased significantly from 36.3 +/- 3.1 ml/min/mm Hg to 41.8 +/- 3.5 ml/min/mm Hg (p less than 0.001). These data demonstrate that pentoxifylline improves gas exchange, possibly by increasing cardiac output, and/or by raising mixed venous PO2, and/or by improving blood flow to underperfused alveoli.