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A randomised controlled study evaluating sildenafil-pentoxifylline combination therapy in the management of erectile dysfunction

Law , YXT1; Mani, LRN1; Tai, BC2; Lee, KCJ1

1: National University Hospital, Department of Urology, Singapore; 2: National University of Singapore, Saw Swee Hock School of Public Health, Singapore

Objective: The aim of this study was to evaluate the efficacy of pentoxyfiline (a non-specific PDE inhibitor) as an adjunctive treatment for patients with severe ED. This study compares the relative efficacy when sildenafil is used as monotherapy with sildenafil-pentoxyfiline combination therapy.

Material and Method(s): The study was a prospective, randomized, double-blind, placebo-controlled trial, single centre study. Subjects were recruited between April 2014 and November 2016 from the National University Hospital, Singapore. The treatment period/ duration of study was for 8 weeks. Efficacy was measured via IIEF-5 at week 8.

Results: Fifty patients were randomized into 2 groups (27 belonging to the group receiving combination therapy, 23 belonging to the group receiving sildenafil monotherapy). Patients in the 2 groups were comparable in terms of the demographic and clinical characteristics with no significant difference in age, comorbidities and baseline IIEF-5 scores (13±5SD). The mean IIEF-5 score of combination group vs monotherapy group was 14.11 and 14.87 respectively. There was no significant difference between the outcomes of these 2 groups 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 group compared to the monotherapy group- even after adjustment for baseline scores (Mean difference 1.11, 95% CI 0.10 to 2.12, p = 0.032). Adverse events (AEs) include gastrointestinal, neurological, musculo-skeletal and dermatological. Of these, gastrointestinal AEs like abdominal discomfort and distension were most common (40% overall).

Conclusions: This is the first prospective, randomised, double-blind, placebo-controlled trial reviewing the relative efficacy of combination therapy sildenafil + pentoxyfiline vs sildenafil monotherapy. Our study suggests that the use of combination therapy does not improve the management of patients compared to monotherapy. This is in contrast with previous pilot studies (having similar recruitment numbers) which had demonstrated enhanced efficacy of combination therapy compared to monotherapy. Overall, there was no difference with respect to the incidence of AEs between the two treatment arms.


Work supported by industry: no.

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