Long-term Effects of Lipase Inhibition by Orlistat on Gastric Emptying and Orocecal Transit Time of a Solid Meal

Background: We assessed the impact of a prolonged lipase inhibition upon gastric emptying (GE) and orocecal transit time (OCTT) of a 355-kcal low-fat solid meal.

Methods: In double-blind manner, 40 obese women BMI > 30 kg/m2, randomly allocated into two equal groups, took orally t.i.d. 120 mg orlistat or placebo during 8 weeks of a weight-reducing management. At randomization and after 2 months, GE was measured simultaneously with OCTT by means of a 13C-octanoic acid and a hydrogen breath test, respectively. Lipolytic activity was evaluated with a 13C-mixed triglyceride breath test (13C-MTGBT).

Results: A profound lipase inhibition by orlistat was confirmed by a 79.5% +/- 16.9% reduction of the cumulative 6-h 13C recovery with 13CMTGBT. GE remained unchanged either in the orlistat (T1/2, 188 +/- 35 min start versus 198 +/- 36 min end) or the placebo (T1/2, 191 +/- 35 min start versus 180 +/- 39 min end) group. OCTT increased from 208 +/- 54 min to 271 +/- 64 min (P < 0.01) after orlistat treatment and did not change significantly (216 +/- 76 vs. 234 +/- 72 min) in the placebo group.

Conclusions: No adverse effect on the GE and a moderate prolongation of the OCTT of a low-fat solid meal is to be expected under a prolonged treatment with orlistat at a typical dosage regimen.