Possible therapeutic use of loperamide for symptoms of lactose intolerance

To examine a potential practical therapeutic use of loperamide (Lo) to decrease the symptoms of lactose intolerance.

Nineteen (eight men, 11 women) healthy lactose maldigesters (18 of 19 with symptoms) underwent a 25 g lactose challenge on five separate days. Breath hydrogen was measured, areas under the curve (AUC) were calculated for 4 h, and 4 and 12 h symptom scores were recorded. After establishing baseline measurements, test doses of 4 mg, 8 mg and 12 mg Lo were randomly administered without placebo in a double-blind manner. As well, each subject received seven lactase tablets, in a random, unblinded manner.

The median AUC and mean oral cecal transit time followed dose response expectations; however, only lactase treatment achieved significance. Nevertheless, 8 mg Lo significantly improved symptom scores, which were statistically indistinguishable from those of lactase. Four subjects complained of delayed constipation and cramps with various doses of Lo.

Lo monotherapy for lactose intolerance is not economical and may have some side effects. However, Lo may be studied further as an adjunctive treatment of lactose intolerance in an effort to reduce the need for complete lactose digestion. Such a manoeuvre may allow rapid colonic adaptation, which in turn may be beneficial for prophylaxis for a number of colonic diseases.