My father severly suffering from ibs from last more than 18y. he become very possesive, weak & depressive in these days. i want proper medication.

See you have listed: Depression. Is he being treated for this. If not, would encourage a psychiatric evaluation. At that time it could be determined if he would benefit from a psychiatric medication. The psychiatrist can recommend the optimum medication. Talking therapy is also very important.

You need a local doc: Hi, I'm very sorry to hear of your father's suffering. It is a very terrible disease and a burden to carry for such a long time. Unfortunately IBS can sometimes also be very difficult to treat and I would recommend a local doctor that he can be seen by that can follow up with him on a frequent basis. I hope you can find a good doctor to help. Hang in there!