CONTEXT

Acute diarrhea with gas-related abdominal discomfort is a common, usually self-limited disorder with substantial social and economic impact.

OBJECTIVE

To compare the efficacy and safety of a loperamide hydrochloride-simethicone combination product with those of loperamide alone, simethicone alone, and placebo in treating acute diarrhea with gas-related abdominal discomfort.

DESIGN

Randomized, placebo-controlled, double-blind trial of 48 hours' duration.

SETTING

A primary care, ambulatory practice in Acapulco, Mexico.

PATIENTS

A total of 493 outpatient adults aged 18 to 63 years, with acute nonspecific diarrhea with at least moderately severe abdominal discomfort.

INTERVENTIONS

Each patient was randomly assigned to receive 2 chewable tablets containing loperamide hydrochloride, 2 mg, and simethicone, 125 mg (n = 124); loperamide hydrochloride, 2 mg (n = 123); simethicone, 125 mg (n = 123); or placebo (n = 123). This was followed by 1 tablet after each unformed stool, up to 4 tablets in any 24-hour period.

MAIN OUTCOME MEASURES

Time to last unformed stool and time to complete relief of gas-related abdominal discomfort were the protocol-specified primary outcomes. Secondary outcomes included time to complete relief of diarrhea, number of unformed stools, and patient-assessed variables at the end of the study (overall illness relief, diarrhea relief, and abdominal discomfort relief).

RESULTS

Patients who received loperamide-simethicone had significantly (P < .001) shorter time to last unformed stool and faster relief of gas-related abdominal discomfort than patients who received loperamide, simethicone, or placebo alone. Loperamide-simethicone was significantly (P < or = .01) more effective than the other 3 treatments for all end-of-study patient-assessed outcomes and all clinically important secondary outcomes. No significant differences in adverse events were found among treatment groups.

CONCLUSIONS

The loperamide-simethicone combination chewable product provides faster and more complete relief of acute nonspecific diarrhea and associated gas-related abdominal discomfort (gas pain, cramps, gas pressure, and bloating) than either of its components or placebo. The combination is well tolerated.