I Have Problem Of Constipation Since Many Years. Two Years

i have problem of constipation since many years. Two years back, after doing some exercises i felt a little pain in the disc area at back and at some points in the left leg and it continued for a couple of months. After consulting a doctor i came to know it was mild sciatica. Doctor advised oral vitamin D3 sachets once a week for 3-4 months, due to which the problem of constipation maximized to piles. Since then i have a problem of IBS and last 5 months dyspepsia also. Doctor has advised rabisec (before meals), lesuride and normaxin (after meals) but also mention that don't take it for a long time. But as soon as i discontinue the use the symptoms start prevailing after 10-15 days and i start the medicines again. Please help if any other cure for the problem is there?