Influence of the pharmacological modification of gastric emptying on lactose digestion and gastrointestinal symptoms.

Background: In lactose maldigesters the ingestion of food which retards gastric emptying improves tolerance to lactose.

Aim: To study the effects of the pharmacological modification of gastric emptying on the speed of development of lactose-induced symptoms.

Methods: After an overnight fast, 18 lactose maldigesters were given, in a randomized double-blind study design at 1-week intervals, either propantheline (as bromide 15 mg), metoclopramide (as hydrochloride 10 mg) or placebo, in identical capsules, 60 min before ingesting 50 g lactose coloured with 1 g carmine dye (to measure gastrointestinal transit time). Gastrointestinal symptoms, urinary galactose excretion, and breath hydrogen and blood glucose concentrations were recorded.

Results: The propantheline-induced prolongation of gastric emptying improved tolerance to lactose, as measured by reduced area under the gastrointestinal symptom score curve 0-12 h, compared to placebo (by 26%) (P < 0.05) or metoclopramide (by 30%) (P < 0.05). The total hydrogen excretion AUC (180 min follow-up) increased by 15% after metoclopramide as compared with placebo (P = 0.18). Propantheline decreased this variable by 15% from placebo (P = 0.17). No significant differences in blood glucose, urinary galactose or gastrointestinal transit time were found.

Conclusions: In an oral lactose tolerance test, delaying gastric emptying with propantheline improved tolerance in lactose maldigesters, as measured by diminished gastrointestinal symptoms and reduced breath hydrogen concentration.