Below are links to additional sources of information on premature ejaculation (PE).

On-demand use of tramadol, sildenafil, paroxetine and local anesthetics for the management of premature ejaculation: A randomized placebo-controlled clinical trial: (https://pubmed.ncbi.nlm.nih.gov/26558110/)

Pharmacotherapy of premature ejaculation: a systematic review and network meta-analysis: (https://pubmed.ncbi.nlm.nih.gov/30225547)

Phosphodiesterase Type 5 Inhibitors for Premature Ejaculation: A Systematic Review and meta-analysis: (https://pubmed.ncbi.nlm.nih.gov/28720356)

Efficacy and safety of phosphodiesterase type 5 inhibitors on primary premature ejaculation in men: (https://pubmed.ncbi.nlm.nih.gov/26791333/)

Tramadol for the Management of Premature Ejaculation: (https://www.nature.com/articles/ijir20157)

Safety and Efficacy of Tramadol Hydrochloride on Treatment of Premature Ejaculation: (https://pmc.ncbi.nlm.nih.gov/articles/PMC3739134/)

The Use of Tramadol “On-demand” for Premature Ejaculation: A Systematic Review: (https://www.goldjournal.net/article/S0090-4295(12)00980-6/abstract)

On-demand Tramadol Hydrochloride Use in Premature Ejaculation Treatment: 

(https://www.sciencedirect.com/science/article/abs/pii/S0090429511024459)

Tramadol is an Effective Therapy for Mild to Severe Premature Ejaculation: (https://www.nature.com/articles/nrurol.2011.138)