We will consider the patients with LPE non-responding to dapoxetine treatment when they used the optimum dose (30 and 60mg) dapoxetine for 4 separate times with no response.~Serum vitamin D, vitamin B12, and folic acid levels will be assessed in all subjects included in the study. Venous blood samples will be drawn and kept into EDTA bottles in the morning between 8 and 10 a.m. after an overnight fast of about 10-14 hr.
Therefore, this study will aim to assess serum levels of vitamin D, vitamin B12 and folic acid among patients with lifelong PE and non-responding to dapoxetine treatment.