Suggest Alternate Medicine For IBS Other Than Mebravine

I have mebravine tablets as I suffer from ibs but not often. Have not needed to take any medication for some time but the last few weeks the pain in my upper stomach above my belly button has been coming and going. I feel bloated and then the cramp like pain come and go at times making me feel faint and sick. What is the best medication to take as the mebravine don't seem to be working?