Pentoxifylline for intermittent claudication

Abstract

Background: Intermittent claudication (IC) is a symptom of peripheral arterial disease (PAD) and is associated with high morbidity and mortality. Pentoxifylline, one of many drugs used to treat IC, acts by decreasing blood viscosity, improving erythrocyte flexibility and promoting microcirculatory flow and tissue oxygen concentration. Many studies have evaluated the efficacy of pentoxifylline in treating individuals with PAD, but results of these studies are variable. This is an update of a review first published in 2012. Objectives: To determine the efficacy of pentoxifylline in improving the walking capacity (i.e. pain-free walking distance and total (absolute, maximum) walking distance) of individuals with stable intermittent claudication, Fontaine stage II. Search methods: For this update, the Cochrane Vascular Group Trials Search Co-ordinator searched the Specialised Register (last searched April 2015) and the Cochrane Register of Studies (2015, Issue 3). Selection criteria: All double-blind, randomised controlled trials (RCTs) comparing pentoxifylline versus placebo or any other pharmacological intervention in patients with IC Fontaine stage II. Data collection and analysis: Two review authors separately assessed included studies,. matched data and resolved disagreements by discussion. Review authors assessed the methodological quality of studies by using the Cochrane 'Risk of bias' tool and collected results related to pain-free walking distance (PFWD) and total walking distance (TWD). Comparison of studies was based on duration and dose of pentoxifylline. Main results: We included in this review 24 studies with 3377 participants. Seventeen studies compared pentoxifylline versus placebo. In the seven remaining studies, pentoxifylline was compared with flunarizine (one study), aspirin (one study), Gingko biloba extract (one study), nylidrin hydrochloride (one study), prostaglandin E1 (two studies) and buflomedil and nifedipine (one study). The quality of the evidence was generally low, with large variability in reported findings. Most included studies did not report on random sequence generation and allocation concealment, did not provide adequate information to allow selective reporting to be judged and did not report blinding of assessors. Heterogeneity between included studies was considerable with regards to multiple variables, including duration of treatment, dose of pentoxifylline, baseline walking distance and participant characteristics; therefore, pooled analysis was not possible. Of 17 studies comparing pentoxifylline with placebo, 14 reported TWD and 11 reported PFWD; the difference in percentage improvement in TWD for pentoxifylline over placebo ranged from 1.2% to 155.9%, and in PFWD from -33.8% to 73.9%. Testing the statistical significance of these results generally was not possible because data were insufficient. Most included studies suggested improvement in PFWD and TWD for pentoxifylline over placebo and other treatments, but the statistical and clinical significance of findings from individual trials is unclear. Pentoxifylline generally was well tolerated; the most commonly reported side effects consisted of gastrointestinal symptoms such as nausea. Authors' conclusions: Given the generally poor quality of published studies and the large degree of heterogeneity evident in interventions and in results, the overall benefit of pentoxifylline for patients with Fontaine class II. intermittent claudication remains uncertain. Pentoxifylline was shown to be generally well tolerated. Based on total available evidence, high-quality data are currently insufficient to reveal the benefits of pentoxifylline for intermittent claudication.