Despite new guidelines and research in favor of split dosing, skeptics remain. “We’ve heard from a lot of physicians that they don’t want to inconvenience their patients by getting up that early or that patients simply won’t do it,” said Jeff Driggs, associate brand director of marketing at Salix Pharmaceuticals Inc.
Salix Pharmaceuticals has two bowel preps: OsmoPrep and MoviPrep. OsmoPrep is a sodium-phosphate-based tablet prep, and MoviPrep is peg-based. Driggs said they are the only two FDA-approved bowel preps for split dosing.
“Some physicians don’t want to push their patient to do it or patients won’t do it,” Driggs added. “But physicians are realizing that once every 10 years that gives them the best opportunity to see it. If they’re doing all that, there should be some incentive on the patient side to get the best prep.”
In 2008, Driggs said his company asked 1,057 patients in a survey if they would be willing to get up at 3 a.m. to take a second dose of bowel prep if the benefits were properly explained—83 percent said they would.
“Look at it this way, though,” Rex wrote in The New York Times. “You may undergo colonoscopy as infrequently as every 10 years. Therefore, you want the doctor to have the best possible shot at making sure your colon is normal. If you get up during the night for things like crying babies or sick family members, you can do it to avoid dying from colorectal cancer. So if you want that early morning appointment, let the doctor know you’re willing to get up and take the second half of the preparation.”
In addition to patient inconvenience, some anesthesiologists also have taken issue with split dosing. “Another reason that split-dosing is not used is that some anesthesiologists won’t let patients drink fluids after midnight, or for six to eight hours before they are sedated,” Rex wrote. “They are worried that the patient may vomit and inhale fluids during the procedure. But this concern is misplaced. The evidence shows that when people are drinking only clear liquids, the same amount of liquid is left in the stomach whether you stop fluid intake two hours before the procedure or many hours before.”
The American Society of Anesthesiology guidelines said the patient should have nothing by mouth two hours prior to a procedure. The new ACG guideline is consistent with this.
“The idea of splitting the dose is two-fold,” said Driggs. “Some physicians will split the dose during a certain time period the night before a procedure because they think either spreads out the issues of bloating and the nausea. The real idea behind split dosing is getting the second dose of the bowel prep as close to the procedure time, the day of the procedure, as possible.”
“If they prep the night before, the patient is going to move out the majority of the stool and will push through,” Driggs said. “A colonoscopy, in general, shows a 90 percent capture rate of finding polyps and pre-cancerous polyps. That’s still a 10 percent differential. So doctors are obviously trying to get to 100 percent.”
Safety is always the bottom line, and physicians want the best techniques.
“Doctors want something that’s simple,” Driggs said of split dosing. “When the patient shows up, they’re clean, they can get in and spend the amount of time they need to looking for polyps.”