Very few serious ones, though the preparations commonly recommended by doctors can cause nausea, vomiting, painful cramping, dehydration, electrolyte disturbances, kidney damage and even fainting. In very rare instances, a tablet called Visicol has been linked with seizures and a team of Columbia University researchers reported recently on 21 patients who suffered acute kidney failure after colonoscopy preparations.
A colonoscopy is a procedure, usually done under light sedation, in which a doctor examines the inside of the colon with a lighted “scope” or viewing tube.
Colonoscopies save lives by catching pre-cancerous polyps and removing them before they can become dangerous, said Dr. Anthony Kalloo, chief of gastroenterology and hepatology at Johns Hopkins Hospital. Overall, an estimated 155,290 Americans will be diagnosed with colorectal cancer this year and 56,290 will die.
To prepare for the exam, patients must clean all fecal material out of the colon, a process many people find more unpleasant than the exam itself. There are several ways to do this. One way is to drink a gallon of prescription solution such as GoLytely, Colyte or NuLytely . They are effective at cleaning out the colon, but can sometimes cause gastrointestinal upset, said Dr. Rosaline Barron, a gastroenterologist at Mount Auburn Hospital in Cambridge.
A second approach, which many patients find easier but which doesn’t always cleanse the colon quite as well, Barron said, is to use Fleet Phospho-Soda, an over-the-counter liquid that the patient takes in two 3-tablespoon doses, mixed with ginger ale. This method can cause problems for people with kidney disease or congestive heart failure, making it “basically a young and healthy person’s prep,” said Barron.
A third method is HalfLytely, which means drinking only half, not a full gallon, of solution, though the colon may not get clean enough. Patients also take two to four Dulcolax tablets.
Finally, for people who really can’t stand drinking the solution, there is a pill-only prep. The patient takes 28 to 32 pills of Visicol, but this carries the same risks as the Fleet Phospho-Soda and sometimes may not yield a clean enough colon.
Talk with your doctor about the most gentle and effective prep for you – regimens can usually be individually tailored for even the frailest patients.