Dose-dependent gastrointestinal effects of the somatostatin analog lanreotide in healthy volunteers

Objective: To investigate the gastrointestinal effects of intravenous lanreotide. Methods: Twenty healthy male subjects participated in 2 subsequent placebo-controlled, double-blind crossover studies. The effects of 3 doses of lanreotide (50, 100, and 200 mu g/h) were investigated on 24-hour intragastric acidity (study I), food-stimulated gallbladder contraction, and plasma cholecystokinin release (study II). Results: Lanreotide showed linear pharmacokinetics. It raised median intragastric pH significantly and in a dose-dependent manner: from 1.4 +/- 0.2 (placebo) to 2.5 +/- 0.8 (P < .002) during administration of 50 mu g/h lanreotide, to 3.2 +/- 0.7 (P < .001) during 100 mu g/h lanreotide, and to 4.3 +/- 0.7 (P < .001) during 200 mu g/h lanreotide. However, no significant inhibition of gastrin secretion could be established. All doses completely inhibited postprandial gallbladder contraction, Conclusion: Intravenous administration of lanreotide at rates applied in this study was able to significantly inhibit intragastric acid secretion and postprandial gallbladder contraction; under these conditions few untoward effects were noted.