What Are The Side Effects Of Metformin And Glimepiride?

I am taking metformin and glimepiride. I have had extreme difficulty passing stools every since I began medication 2 years ago. I get enough fiber, water, exercise etc. I have had colonscopy; normal. My doctor is stumped.....says maybe IBS; maybe the medication and says no, I can t OD on laxatives. I hate the feeling of almost constantly needing to go but can t.