Drug bioavailability and disposition vary according to body weight and weight loss after bariatric surgery. This study evaluates the impact of body weight and weight loss on the pharmacokinetics of various probe drugs, and compares these effects in three groups of patients receiving either a gall bladder operation, gastric bypass or a very low calorie diet.
This study aims to 1. to investigate the relationship between body composition and the liver/intestine activity and expression of proteins (drug metabolizing enzymes, transporters and regulatory factors) important for drug bioavailability and disposition in the range from normal to morbid obesity (the combined gastric bypass and cholecystectomy groups) at baseline. 2. to compare the short-term (6-week) and long-term (2 years) effect of gastric bypass (GBP) and a very low calorie diet (VLCD) (matched weight loss) on bioavailability and pharmacokinetics of probe drugs (caffeine, omeprazole, digoxin, midazolam, rosuvastatin, losartan) and biomarkers (and adjoining protein expressions) for cytochrome P450 (CYP)1A2, CYP2C9, CYP2C19, CYP3A, P-glycoprotein (gp) and organic anion-transporting polypeptide (OATP)1B1. 3. to compare the 3 study groups (GBP, VLCD and cholecystectomy) at baseline with respect to body composition, cardiovascular risk factors and metabolic biomarkers. 4. to compare the short-term (6-week) changes in glucose metabolism, blood pressure, blood lipids and body composition of matched weight loss and long-term effects (2 year) on body composition, cardiovascular risk factors and metabolic biomarkers, between the GBP and VLCD groups.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
100
Weight loss surgery
Non-surgical weight loss procedure
HVestfold
Tønsberg, Vestfold, Norway
Bioavailability of drugs (1)
Changes in absolute bioavailability (Area Under Curve - oral / Area Under Curve -intravenous) of midazolam after Gastric Bypass and Very Low Calorie Diet, respectively.
Time frame: 0 hours and 0.25, 0.5, 1, 1.5, 2, 3, 4, 4.25, 4.5, 5, 5.5, 6, 8, 10*, 12*, 23 and 24 hours following administration
Bioavailability of drugs (2)
Changes in bioavailability (Area Under Curve - oral) of caffeine, losartan, digoxin, rosuvastatin and omeprazole after Gastric Bypass and Very Low Calorie Diet, respectively.
Time frame: 0 hours and 0.25, 0.5, 1, 1.5, 2, 3, 4, 4.25, 4.5, 5, 5.5, 6, 8, 10*, 12*, 23 and 24 hours following administration
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