Glucagon and Colonoscopy

Glucagon transiently decreases peristalsis of smooth muscle in the gastrointestinal tract. It
is widely used by radiologists to improve diagnostic yields of upper and lower GI barium
contrast examinations. Glucagon is also routinely administered intravenously for all
endoscopic retrograde cholangiopancreatography (ERCP) throughout the United States to
facilitate canulation of the duodenal papilla and sphincterotomy. Glucagon has been used at
the dose of 1-3 mg intravenously by Dr. John Cello in over 5000 ERCP examinations. The role
of glucagon in facilitating colonoscopy remains controversial however and is not considered
"routine". Several studies have evaluated the effect of glucagon on colonoscopy with varying
results. No large scale randomized controlled trial has been performed to conclusively
establish the effect of routine glucagon administration prior to colonoscopy. The
investigators plan to carry out a randomized double blind, placebo controlled trial that
studies key parameters of a colonoscopy such as cecal intubation time, withdrawal time, total
procedure time, adenoma detection rate, endoscopist's assessment of the difficulty of the
procedure, patient comfort, and patient's willingness to undergo a repeat colonoscopy.

Inclusion Criteria:

- Any subject who has already been already cleared for and scheduled to undergo
colonoscopy at SFGH endoscopy center.

Exclusion Criteria:

1. Refusal to give informed consent.

2. Age <18 or >70.

3. Prior intra-abdominal surgery

4. Diabetes

5. Pheochromocytoma

6. Insulinoma

7. Liver disease (Child-Pugh Score >6)

8. Pregnancy