The well established bowel cleansing method using a polyethylene glycol-based solution (Fordtran) is limited by the necessity of large volume intake, which proves difficult for many patients. Therefore, a new method using small volumes (2 x 90 ml) of oral sodium phosphate is employed more and more frequently. Its only disadvantage is the occurrence of considerable nausea or occasional vomiting in about 25% of patients. To ascertain whether nausea could be reduced, 426 patients were given an antiemetic (ondansetron, metoclopramide, cisapride) or placebo on a randomized, double-blind basis, one hour before sodium phosphate intake.
Results: sodium phosphate was well tolerated in 69.2% of the patients on placebo, 73.6% on cisapride, 76.5% on metoclopramide and 80.4% on ondansetron. Taking all four groups together, male patients exhibited much better tolerance (86.1%) than females (66.1%). Severe nausea and/or emesis was noted in 22.4% of patients on placebo, 21.7% on cisapride, 17% on metoclopramide and 14% on ondansetron. In over 90% of patients colon cleansing was rated as good to very good. This was largely independent of the severity of nausea. 129 patients who had undergone former polyethylene glycol-based lavage judged sodium phosphate to be more tolerable and easier to complete. Considering known contraindications (symptomatic congestive heart failure and/or renal failure), no serious adverse event was noted in any of the 426 patients investigated. In accordance with several recent studies, we consider sodium phosphate solution at present the procedure of choice for colon cleansing. Compared to Fordtran, patient acceptance is far better and cleansing quality superior. Routine antiemetic comedication for reducing possible nausea/vomiting is not worthwhile. On the other hand, this study confirms our former impression of enhanced colon cleansing after administration of an additional mild laxative before sodium phosphate, without interfering with patient acceptance.