Although IELT is an objective measure of ejaculatory function it does not address the impact of therapy on patients' well being and confidence in their sexual performance, which are important markers of treatment benefit. Therefore, if IELT is used as a sole efficacy measure it may not fully characterise the treatment benefit to the patient. For this reason, a patient reported outcome (PRO) known as the Index of Premature Ejaculation (IPE) will be used in this study in conjunction with IELT to evaluate efficacy. Thus the combination of the objective measure of ejaculatory latency with the PRO of IPE should be able to provide efficacy data which are representative of clinical benefit to the patient.