Thank you for your question.
Premature ejaculation is a very common problem. Apart from a small percentage of men, most cases are due to learning to masturbate in a hurry. So delaying ejaculation is also a learnt behaviour. There are several causes for why some men never manage to learn to delay ejaculation but anxiety is a huge factor. Whatever medicine you take, if you cannot relax, do pelvic floor exercises and manage your arousal the problem will persist.
Dapoxetine and several other drugs used in premature ejaculation essentially stop you from feeling so aroused. If you can learn to that you may be able to avoid medication and its related side effects.
hope this helps
you can try reading 'Managing premature ejaculation' by Metz and Mc Carthy.