Easing the Discomfort of Colonoscopy

From the WebMD Archives

April 7, 2000 (Lake Worth, Fla.) -- Many people who have a colonoscopy, a comprehensive but often painful screening test for colon cancer, complain that they are not adequately sedated. Researchers who set out to determine whether patients could get better results by controlling the sedation themselves found that these patients had no less pain than those who were sedated normally.

Colonoscopy is one of several tests for colon cancer. This type of cancer will kill approximately 56,000 people in the U.S. this year, and many of these deaths could be avoided with early detection. According to the American Cancer Society, early detection can increase survival by 90%, but only 37% of colon cancers are detected early.

The study from Haifa, Israel, compared normal sedation with patient-controlled sedation to see whether the test might be more easily tolerated if the patients could determine when they needed more medication.

"[D]issatisfaction with the level of sedation and analgesia is relatively common among patients undergoing colonoscopy," Edy Stermer, MD, and her colleagues write in the March issue of Gastrointestinal Endoscopy.


The researchers found that allowing patients to push a button and receive more pain medication did not lead to them having any less pain overall than patients who were given more pain medication by the doctor. Both groups of patients used the same amount of medication. Although there was some concern about the safety of allowing patients to give themselves more medication, both groups tolerated the colonoscopy equally well.

Michael Pignone, MD, MPH, tells WebMD that he thinks standard sedation is probably adequate, and that is why there was no benefit to allowing patients to give themselves more pain medication. Pignone, an associate professor in the division of internal medicine at the University of North Carolina in Chapel Hill, was not a part of the Israeli study.

Colonoscopy is a 20- to 30-minute procedure in which a flexible, lighted instrument about the diameter of an index finger is inserted into the anus to enable the physician to examine the colon. Patients are generally awake for it, but sedation is usually used to relieve the discomfort.


"The sedation makes one feel light-headed," Glenn Eisen, MD, MPH, tells WebMD. Fortunately, the sedative that is used also causes amnesia, "so the patient may well not remember the procedure," he says. Patients having the procedure cannot be "put out" completely, as that would require a breathing machine, Eisen says, and that carries greater risks than the colonoscopy itself. Eisen is an associate professor of medicine and director of endoscopy at Vanderbilt University Medical Center in Nashville, Tenn.

Ever since Today Show host Katie Couric televised her own colonoscopy, interest in the procedure has risen. However, colonoscopy isn't the only way to screen for this disease, and it may not be needed by everyone.

Other screening methods for colon cancer include the fecal occult blood test (FOBT), a test that can detect microscopic amounts of blood in the stool; the flexible sigmoidoscopy ("flex sig"), which is much like the colonoscopy, but explores a smaller amount of the large intestine; and the double contrast barium enema, which uses dye inserted into the colon to make tumors, benign or cancerous, visible on X-ray.


In previous research, Pignone found that the more informed patients are about the examinations and the disease, the more likely they are to get early screening. People need to know, he says, that "people over 50 are at risk, [and] screening can reduce cancer cases and deaths."

According to the American Cancer Society, everyone should get an FOBT and a flexible sigmoidoscopy at age 50. If the results are normal, the FOBT should be repeated annually and the sigmoidoscopy every five years. Or, the patient could then have a colonoscopy (repeated every 10 years if normal) and/or a double-contrast barium enema (repeated every five to 10 years if normal)

People at high risk for colon cancer, such as those with a family history of the disease, may need to start screening before age 50.

Vital Information:

  • Colonoscopy is a procedure in which a flexible, lighted instrument is inserted into the anus to examine the colon. It usually requires sedation.
  • A new study shows that normal sedation is just as effective as patient-controlled sedation.
  • Colonoscopy is one of many tests that can be used to screen for colon cancer; others include the fecal occult blood test, flexible sigmoidoscopy, and contrast barium enema.
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