Hi,
Thanks for posting your query at DoctorSpring.com. I am Dr.R.K and I am pleased to assist you.
You have mentioned enlarged colon was diagnosed when you were 13. This usually results when your bowel movements are not normal for a long time.
Miralax and Citrucel are very effective in relieving constipation. If you are not responding to these two then you may have to undergo a few tests to find the cause. First you may have to undergo a colon transit study to see how your colon is working. Since you are on a trip now, this may not possible right now. You can consider doing this after returning to your place.
For the time being, you continue taking Miralax and Citrucel. You need to drink lot of fluids and eat high fiber diet ( lot of vegetables and fruits). Drink lot of prune juice which is very effective. Also try to avoid medications like cough syrups and opioid painkiller medications which cause constipation.
I hope that answers your question. Would be glad to answer any follow-up queries.
Regards,
Dr.R.K