Miralax and the other laxatives you have to drink before a colonoscopy are made with PEG, a petroleum byproduct, which can trigger neurological symptoms in some people, including those with small fiber neuropathy. I avoid PEG because the last time it sent me into a major flare. I will ask for an alternative, Lactulose, for my next colonoscopy. But this is a sugar alternative and would not be suitable for those with diabetes. The colonoscopy itself was no big deal.