Objective: To compare efficacy and tolerability of a loperamide/simethicone (LOP/SIM) combination product with that of loperamide (LOP) alone, simethicone (SIM) alone, and placebo (PBO) for acute nonspecific diarrhea with gas-related abdominal discomfort.
Research design and methods: In this multicenter, double-blind, 48-h study, patients were randomly assigned to receive two tablets, each containing either LOP/SIM 2 mg/125 mg (n = 121), LOP 2 mg (n = 120), SIM 125 mg (n = 123), or PBO (n = 121), followed by one tablet after each unformed stool, up to four tablets in any 24-h period. The primary outcome measures were time to last unformed stool and time to complete relief of gas-related abdominal discomfort. For time to last unformed stool, an unformed stool after a 24-h period of formed stools or no stools was considered a continuance of the original episode (stricter definition) or a new episode (alternate definition).
Results: A total of 483 patients were included in the intent-to-treat analysis. The median time to last unformed stool for LOP/SIM (7.6 h) was significantly shorter than that of LOP (11.5 h), SIM (26.0 h), and PBO (29.4 h) (p < or = 0.0232 in comparison with survival curves) using the alternate definition; it was numerically but not significantly shorter than that of LOP (p = 0.0709) and significantly shorter than that of SIM and PBO (p = 0.0001) using the stricter definition. LOP/SIM-treated patients had a shorter time to complete relief of gas-related abdominal discomfort than patients who received either ingredient alone or placebo (all p = 0.0001). Few patients reported adverse events in the four treatment groups, none of which were serious in nature. Potential study limitations include the ability to generalize study results to the population at large, variability in total dose consumed, and subjectivity of patient diary data.
Conclusions: LOP/SIM was well-tolerated and more efficacious than LOP alone, SIM alone, or placebo for acute nonspecific diarrhea and gas-related abdominal discomfort.