Sustained-release Morphine Pharmacokinetics in Roux-en-Y Gastric Bypass Subjects

The purpose of this study is to determine whether sustained release morphine pharmacokinetics parameters in patients undergone roux-en-y gastric bypass (RYGB) differ from subjects who did not. Our hypothesis is that exposure is comparable. Indeed, in the Study OBEMO (Determinants of Oral Morphine Answer Among Obese Patients Before and After Gastric Bypass; NCT00943969) the investigators observed changes in pharmacokinetics parameters for immediate release morphine, probably due to an earlier absorption of the morphine, in agreement with the expected clinical effect of this formulation.