Influence of loperamide on lactose handling and oral-caecal transit time.

BACKGROUND

The influence of pharmacologically prolonged oral caecal transit time on lactose handling is examined in the wake of finding improved lactose handling during naturally occurring prolonged oral-caecal transit time.

METHODS

Sixteen normal male volunteers with lactose maldigestion were pretreated with 8 and 12 mg loperamide on different days and lactose handling was compared by measuring areas under the curve during lactose breath H2 testing (3 h). The oral-caecal transit time was similarly measured using lactulose and exhaled breath H2. Symptom scores were recorded and, in three subjects, blood sugar was simultaneously measured.

RESULTS

The mean +/-S.E.M. baseline oral-caecal transit time was 56.9 +/- 5.9 min. Loperamide significantly prolonged oral-caecal transit time (90.3 +/- 11.1 and 82.1 +/- 13.9 min for 12 and 8 mg loperamide, respectively; P < 0.05). The lactose breath H2 area under the curve with 12 mg loperamide was significantly less than at baseline (7685 +/- 985.6 vs. 10243.1 +/- 1607, respectively; P < 0.05). Significantly fewer symptoms were recorded with both doses of loperamide during the 3 h test but with 12 mg loperamide only on follow-up. There was no significant rise in blood sugar at any time in the three subjects studied.

CONCLUSIONS

Loperamide-induced graded prolongation of oral-caecal transit time is associated with significantly improved lactose handling as measured by a reduction of the area under the curve. Symptoms of lactose intolerance may also be improved with loperamide. Prolongation of oral-caecal transit time with loperamide may be useful as adjunctive or primary therapy of carbohydrate intolerance in patients with rapid transit.