Background: Tramadol is a centrally acting analgesic prescribed off-label for the treatment of premature ejaculation (PE). However, tramadol may cause addiction and difficulty in breathing and the beneficial effect of tramadol in PE is yet not supported by a high level of evidence. The purpose of this study was to systematically review the evidence from randomised controlled trials (RCT) for tramadol in the management of PE.

Methods: We searched bibliographic databases including MEDLINE to August 2014 for RCTs. The primary outcome was intra-vaginal ejaculatory latency time (IELT). Methodological quality of RCTs was assessed. Between-group differences in IELT and other outcomes were pooled across RCTs in a meta-analysis. Statistical and clinical between-trial heterogeneity was assessed.

Results: A total of eight RCTs that evaluated tramadol against a comparator were included. The majority of RCTs were of unclear methodological quality due to limited reporting. Pooled evidence (four RCTs, 721 participants), suggests that tramadol is significantly more effective than placebo at increasing IELT over eight to 12 weeks (p = 0.0007). However, a high level of statistical heterogeneity is evident (I-squared = 74%). Single RCT evidence indicates that tramadol is significantly more effective than paroxetine taken on-demand, sildenafil, lidocaine gel, or behavioural therapy on IELT in men with PE. Tramadol is associated with significantly more adverse events including: erectile dysfunction, constipation, nausea, headache, somnolence, dry mouth, dizziness, pruritus, and vomiting, than placebo or behavioural therapy over eight to 12 weeks of treatment. However, addiction problems or breathing difficulties reported by patients for PE is not assessed in the current evidence base.

Conclusions: Tramadol appears effective in the treatment of PE. However, these findings should be interpreted with caution given the observed levels of between-trial heterogeneity and the reporting quality of the available evidence. The variability across placebo-controlled trials in terms of the tramadol dose evaluated and the treatment duration does not permit any assessment of a safe and effective minimum daily dose. The long-term effects and side effects, including addiction potential, for men with PE have not been evaluated in the current evidence base.

Trial registration: The review is registered on PROSPERO 2013: CRD42013005289 .