GoLytely is superior to MiraLAX as a bowel preparation for screening colonoscopy, Dr. Michael Hjelkrem and his colleagues reported in the April issue of Clinical Gastroenterology and Hepatology.
Although both agents showed adequate bowel cleansing in a prospective, randomized, blinded clinical trial, GoLytely achieved better cleansing of the overall bowel and three individual segments of the colon, as measured by the Ottawa Bowel Preparation Scale (OBPS) score, said Dr. Hjelkrem and his associates at Brooke Army Medical Center in San Antonio (Clin. Gastroenterol. Hepatol. 2011 April [doi:10.1016/j.cgh.2010.11.007]).
GoLytely is one of the safest and most frequently used bowel preparation regimens available, but the large volume (4 L) that patients must drink in a relatively short time, as well as the unpleasant taste attributed to the electrolytes it contains, can make it difficult to tolerate, the authors wrote. Clinicians often use MiraLAX as an alternative because it lacks electrolytes and therefore tastes better, and the volume is more tolerable at 2 L; the MiraLAX was combined with 64 oz of Gatorade. However, MiraLAX is not Food and Drug Administration approved for bowel cleansing before screening colonoscopy.
Until now, no controlled clinical trial has compared the efficacy, safety, and tolerability of the two agents. Both agents were given as split-dose regimens in the study.
The issue is more than just a matter of personal preference, because the regimen’s effectiveness can affect the number of polyps detected, the length of the procedure, and the rate of incomplete procedures. Moreover, improved tolerability may promote better patient compliance and remove a major barrier to undergoing the procedure.
These factors "can translate into health care dollars saved and impact the number of patients who embrace colonoscopy as a valuable screening exam for colon cancer," the researchers said.
Dr. Hjelkrem and his colleagues assessed GoLytely and MiraLAX in a 1-year study in which 425 patients undergoing screening colonoscopy were randomly assigned to bowel prep with GoLytely alone, MiraLAX alone, MiraLAX plus lubiprostone pretreatment, or MiraLAX plus bisacodyl pretreatment. In all, 403 patients completed the colonoscopy.
The average patient age was 54 years (range, 29-80 years) and the average BMI was 30 kg/m2 (range, 19-53). Slightly more than half of patients were men.
GoLytely was more effective for overall bowel cleansing and for cleansing of the ascending, transverse, and descending colon, as measured by the OBPS score. GoLytely yielded an "excellent" score in 49% of patients, compared with only 15% of patients who took MiraLAX alone, 20% of those who took MiraLAX plus bisacodyl, and 19% of those who took MiraLAX plus lubiprostone.
However, all of the bowel prep regimens produced adequate bowel cleansing. And there were no differences in effectiveness among the four treatments across several patient subgroups based on diabetes status, BMI, presence or absence of constipation, or morning vs. afternoon procedure times.
In addition, patients who received GoLytely had a shorter procedure time, but the difference was not statistically significant. There also were no significant differences among the study groups in the number of polyps detected.
Patients rated all three MiraLAX regimens as superior to the GoLytely regimen and reported significantly greater satisfaction with them, even though there were no differences among the regimens with regard to nausea, abdominal bloating, or abdominal cramping. This preference can be attributed to the lower volume of solution they were required to drink "and/or improved taste likely due to the absence of electrolytes," the investigators said.
"We conclude that although MiraLAX is more highly tolerated, it is inferior to GoLytely as a bowel preparation prior to screening colonoscopy.
"For those who value efficacy as the most important variable in bowel preparation, MiraLAX should not be used as first-line therapy. However, for those who value palatability as a major factor in bowel preparation and are willing to forgo some efficacy, MiraLAX may be considered an adequate option," they noted.
Safety concerns have been raised regarding MiraLAX’s absence of electrolytes, because the diarrhea-induced volume depletion during bowel prep might predispose to hyponatremia. "Although we did not check serum chemistry panels on our patients after the preparation, there were no deaths and no side effects resulting in hospitalization. If hyponatremia did occur, it was clinically insignificant in our study subjects," they added.
No conflicts of interest or funding for the study were reported.