The goal of this clinical trial is to learn how GLP-1 and GIP agonists effect bowel preparation in patients scheduled for colonoscopies. The main questions it aims to answer are:

• Does GLP-1 and GIP agonist increase the rate of inadequate bowel preparation?
• Does the quality of bowel preparation differ in patients who hold vs. those who continue a single dose of their GLP-1 or GIP agonist medication?
• Are there any differences in the rates of complications gastric aspiration in patients who hold vs. continue a single dose of their GLP-1 or GIP agonist medication?

Inclusion Criteria:

• Adult patient (Age 18 years or older)
• Patient scheduled for outpatient screening, surveillance, or diagnostic colonoscopy
• Using a GLP-1 or GIP agonist at a stable dose for at least one month

Exclusion Criteria:

• Unable to provide informed consent, e.g., dementia

• Patient refuses the USMSTF recommended bowel cleansing regimen for patients with diabetes or obesity (split-dose 4 liters polyethylene glycol + 15 mg bisacodyl the afternoon before; low residue diet 3 days before colonoscopy; clear liquid diet the day before colonoscopy)

• Risk factors for inadequate bowel preparation besides diabetes and obesity with a likelihood ratio of 1.6 or greater:

  1. Cirrhosis
  2. Parkinson's disease
  3. Dementia
  4. Tricyclic antidepressant use
  5. Opioid use
  6. Gastroparesis* or suspected gastric outlet obstruction on pre-procedure imaging (*defined based on a documented 4-hour solid phase gastric emptying study or prior history of retained gastric contents during upper endoscopy)
  7. Previous colorectal surgery
  8. Prior history of inadequate bowel preparation