A Small Group Randomized Double-Blind Placebo-Controlled Study to Evaluate the Efficacy of Daily Pentoxifylline in the Management of Patients With Erectile Dysfunction with Suboptimal Treatment Response to Sildenafil

Introduction: Several studies have reaffirmed the use of regular pentoxifylline therapy in increasing the penile brachial pressure index in men affected by erectile dysfunction when compared to placebo. Aim: The aim of this study was to evaluate the efficacy of pentoxifylline as an adjunctive treatment for patients with erectile dysfunction. Methods: This study was a single center, prospective, randomized, double-blind, placebo-controlled trial. Subjects were recruited between April 2014 and November 2016 from the National University Hospital, Singapore. The combination therapy group was given pentoxifylline 400 mg thrice daily orally and the monotherapy group was given placebo capsules thrice daily orally. Both groups continued their on-demand 100 mg sildenafil. The treatment duration was 8 weeks. Efficacy was measured via the International Index of Erectile Function (IIEF-5) questionnaire at the eighth week. Differences in mean IIEF-5 score and the domains of the IIEF at 8 weeks between the 2 treatment groups were compared using independent sample t-test. Main Outcome Measure: Baseline IIEF-5 and the IIEF-15 score vs post-therapy IIEF-5 and the IIEF-15 score. Results: 50 patients were randomized into 2 groups. Patients in the 2 groups were comparable in terms of the demographic and clinical characteristics, comorbidities, and baseline IIEF-5 scores. The mean IIEF-5 score post-therapy of the combination therapy group vs the monotherapy group was 14.11 and 14.87, respectively. There was no significant difference between the outcomes of these 2 groups (unadjusted mean difference -0.76; 95% CI -4.01 to 2.49; P = .641) and the outcomes are the same even after adjusting for baseline IIEF-5 scores. There was a significant improvement in the "overall satisfaction" portion of the IIEF score for the combination therapy group as compared to the monotherapy group (unadjusted mean difference 0.12; 95% CI -1.49 to 1.25) and even after adjustment for baseline scores (adjusted mean difference 1.11; 95% CI 0.10 to 2.12; P = .032) the improvement is significant. Conclusion: Our trial suggests that the use of combination therapy does not improve the management of patients compared to monotherapy. Copyright (C) 2019, The Authors. Published by Elsevier Inc. on behalf of the International Society for Sexual Medicine.