Reactions to long-term use of Miralax?

I'm not sure how to answer this. I have been on laxatives for 14 years and think it has definitely screwed up my peristalsis. I am an above knee amputee, endured 68 operations, 23 broken bones, over 1000 days in the hospital, have researched plp over 1000 hours. have been on methadone for the crushing, burning, gnawing pain and have tried nearly 40 diff meds. Lyrica was started mid Dec and has helped the most. What i am getting at is i drink both miralax and have to drink this gunk i buy in Canada called liquid senokot at 2 am so it doesn't mix with my meds, Anyway drank last night and do the miralax and no luck yet, so if doesn't work have to do it all over again. I don't know about the tiredness from the miralax. possible being they are watery that he is losing electrolytes. I just wonder how long he should continue on it. Does he try to eat fiber cereals, fruits, veggies. My metabolism is so slow and i am in a wheelchair, i eat no more then 500 calories a day. Guess i haven't been any help at all. I apologize4., What does the doctor say about continuing laxative. not good for a young boy that prob takes in 2000 or more calories a day to go once or twice a week. Maybe see a gastroenterologist.Pray he won;t need harsher laxatives as body becomes used to them.