Background: Acromegalic patients treated three times daily with subcutaneous injections of the somatostatin analogue octreotide frequently develop gallstones, due to suppressed cholecystokinin release and impaired gall-bladder emptying.
Aim: To elucidate the effects of a new long-acting octreotide formulation (Sandostatin LAR) on gall-bladder emptying, cholecystokinin release and gallstone formation.
Methods: Postprandial gall-bladder and gastric emptying were determined by ultrasonography and cholecystokinin release was measured in seven patients on days 0, 14, 28, and 75 (Sandostatin LAR, 20 mg intramuscularly on days 1, 30, and 60).
Results: During treatment, fasting gall-bladder volumes increased from 26.5 +/- 3.2 mL to 61.4 +/- 7.5 mL, but postprandial cholecystokinin release and gall-bladder emptying (from 63.9 +/- 3.8% to 12.3 +/- 3.5%) were severely suppressed. Gallstones formed in six out of seven patients within 8 months of treatment. Gastric emptying did not change during the therapy.
Conclusions: The risk of gallstone formation is greatly increased during Sandostatin LAR. This is probably related to profound suppression of cholecystokinin release and gall-bladder emptying.