Scheduled for endoscopy and colonoscopy. how risky is prep and procedure? common problems? i have ehlers danlos so hypermobile neck, back, hipsand jaw

Not risky: your ED syndrome will not be an issue. These procedures are performed using a very short acting sedative and very safe in the hands of a skilled endoscopist.

Generally quite safe: Many patients complain of the discomfort of drinking so much liquid: nausea, vomiting, bloating, explosive diarrhea. But only VERY rarely do serious things like seizure/palpitations/kidney failure occur. The large volume of polyethylene glycol solution is safest; the smaller volume oral sodium phosphate solution should not be used; it has been linked to dangerously low phosphate levels.