My bowel motility is severely compromised and it took some time for me to figure out things the doctors were seemingly unconcerned over until a procedure is aborted because of an obstruction. For CFers that suffer from motility issues, and it seems we all do, a standard bowel prep gets about half the job done at twice the cost in misery. My CF father fought the hard fight on the can as am I currently so I have had some time to work this out. The bowel prep overwhelms your system with salts (electrolytes) and a soluble synthetic fiber. Between the two agents, the water you drink and water throughout your body is drawn to the bowels trying to equalize the salts ingested into the gut. The Polyethylene Glycol (Mirilax brand, or PEG) binds up water to form pressure and stimulus for an aggressive bowel movement or ten.
I don’t know how much your motility is impacted by CF and what your regiment to optimize it is but I have to start my own sort of prep prior to taking the Go-Litely or whatever. Instead of Movicol or Mirilax to encourage my regular motility I was prescribed bowel preps to portion daily for motility a couple decades back. Considering that the tastiest bowel prep could gag a maggot, I started breaking down what it was in the bowel prep that did what. Electrolytes, in excess, and an inert bulking fiber like (PEG) make up the drink, and possibly an orange 5mg pill of bisacodyl sodium which is a stimulant laxative that is included, or removed at the pharmacy. There is a reason for the latter to cover later.
If you can take a week or ten days to prepare for your bowel prep, it will go much better. In general taking the components of your bowel prep in less nauseating concentration will prime you for success. An electrolyte rich sports drink (Gatorade or similar) needs to be added or increased to about a quart/twenty-five pounds body weight or a gallon a day for about a week. Adjust this to other liquids you drink in the day as I do trading 16oz. coffee for 8oz. of Gatorade etc. Gravity is so important to the equation and activity such as walking or gardening where the insides get jiggled around is as important to motility as the internal agents we take to help.
Dosing with PEG has been sort of like the black art of enzyme replacement so go with your gut. If you aren’t familiar with PEG as a bulking agent be aware of that definition of "bulking". Although you mix 1/2oz. of PEG or Mirilax with a glass of liquid, it turns into the equivalent of a 16oz. glass of solid food. Imagine a few days worth of this backing up along with regular food and liquids and it sounds pretty miserable. Ideally PEG adds weight and volume to your food as it enters the large bowel. PEG grabs water and keeps hold of it through the digestive system. When our food intake drops due to age or illness, PEG bulks the stool and keeps it pliant. In this way it is a near ideal product, it encourages motility simply by letting your body feel some fecal mass. This is the kindest medicine when it comes to encouraging nature. My point is at a point it is pointless to keep taking it if nothing has moved in several days.
For me if PEG and electrolyte drinks don’t do the job within my comfort zone of time, I take that 5mg bisacodyl sodium. If a person uses common sense with stimulant laxatives, they will serve throughout a lifetime with little risk. Stimulant laxatives are not given in cases of IBS, or the idea is they shouldn't be given. In years when IBS was a dominant issue for me, that little orange pill would hit with a vengance in about an hour.
I applaud you and encourage every CFer to get that baseline colonoscopy and keep current with this exam.
LL