Instead of psyllium, my GI Dr recommended Citrucel, which he said is easier on the digestive system and causes less gas. It comes in flavored power form or capsules. I stopped taking it though because it seemed to give me a stomach ache. I take Miralax every day, which usually works.
I have both fibromyalgia and chronic reflux disease. Plus I have chronic pain in my low back and my neck. Both areas have stenosis, degenerative disc, bulging disc and bone spurs along with arthritis. So I am a patient of pain management, a gastroenterologist at UVA, hormonal specialist in Charlottesville VA as well as my PCP. I am on pain medication that causes constipation and or diarrhea. (Associated with IBS) what works for me is Mirilax but the generic version sold at Sam's club called ClearLAX. It looks just like the bottle of MiraLAX but is a fraction of the cost. I use 1 capful every morning in my coffee. You can't taste it at all. I also take 1 capsule of Dr Schulze's intestinal Formula #1 at night. I do drink 2 liters of water daily. Along with a high fiber diet. I have no problems with constipation.