Dapoxetine is a short acting anti depressant (Ssri) lasts around 4 hrs. One of the side effects of ssri medication is delayed ejaculation.
It does work for some people but not others, mixing it with tadalafil isn't ideal due to the short half life of dapoxetine, it's usually best mixed with a shorter acing generic viagra, I have seen that one of the iops does carry this combination, it may be handy to look for separate dapoxetine (generic priligy) tablets and use the with whatever ED Meds you want.