Is there any same kind of alternative medicine of mebeverine for mild ibs-d. because mebeverine cause me excessive thirst and back pain at mid night?

Quite a few: but first, look for dietary modifications (increased fluid and fiber intake) taht might be helpful in some. Then, older tricyclic antidepressants act through 2 different ways to help (anti-cholingergics shut the gut like mebeverine but are milder; they also lower gut reactions if used at low constant doses). Lomotil, bentyl (dicyclomine) are other gut motility drugs with overlapping side effects to mebeverine.