In the case of the majority of studied drugs , an increased absorption rate was observed early after RYGBP .
The effect on systemic exposure allows for a low degree of extrapolation , including between drugs subjected to the same major metabolic and transporter pathways .
Anatomical changes in the gastrointestinal tract and subsequent weight loss may influence drug disposition and thus drug dosing following bariatric surgery .
This review systematic ally examines the effects of bariatric surgery on drug pharmacokinetics , focusing especially on the mechanisms involved in restricting oral bioavailability .
Drug disposition before and after gastric bypass: fenofibrate and posaconazole.
AIMS Roux-en-Y gastric bypass ( RYGB ) alters the anatomical structure of the gastrointestinal tract , which can result in alterations in drug disposition . The aim of the present study was to evaluate the oral disposition of two compounds belonging to the Biopharmaceutical Classification System Class II - fenofibrate ( bile salt-dependent solubility ) and posaconazole ( gastric pH-dependent dissolution ) - before and after RYGB in the same individuals . METHODS A single-dose pharmacokinetic study with two model compounds - namely , 67 mg fenofibrate ( Lipanthyl ® ) and 400 mg posaconazole ( Noxafil ® ) - was performed in 12 volunteers pre- and post-RYGB . After oral administration , blood sample s were collected at different time points up to 48 h after administration . Plasma concentrations were determined by high-performance liquid chromatography in order to calculate the area under the concentration-time curve up to 48 h ( AUC0 - 48 h ) , the peak plasma concentration ( Cmax ) and the time to reach peak concentration ( Tmax ) . RESULTS After administration of fenofibrate , no relevant differences in AUC0 - 48 h , Cmax and Tmax between the pre- and postoperative setting were observed . The geometric mean of the ratio of AUC0 - 48 h post/pre-RYGB for fenofibrate was 1.10 [ 95 % confidence interval ( CI ) 0.87 , 1.40 ; P = 0.40 ] . For posaconazole , an important decrease in AUC0 - 48 h and Cmax following RYGB was shown ; the geometric mean of the AUC0 - 48 h post/pre-RYGB ratio was 0.68 ( 95 % CI 0.48 , 0.96 ; P = 0.03 ) and the geometric mean of the Cmax pre/post-RYGB ratio was 0.60 ( 95 % CI 0.39 , 0.94 ; P = 0.03 ) . The decreased exposure of posaconazole could be explained by the increased gastric pH and accelerated gastric emptying of fluids post-RYGB . No difference for Tmax was observed . CONCLUSIONS The disposition of fenofibrate was not altered after RYGB , whereas the oral disposition of posaconazole was significantly decreased following RYGB
In the case of the majority of studied drugs , an increased absorption rate was observed early after RYGBP .
The effect on systemic exposure allows for a low degree of extrapolation , including between drugs subjected to the same major metabolic and transporter pathways .
Anatomical changes in the gastrointestinal tract and subsequent weight loss may influence drug disposition and thus drug dosing following bariatric surgery .
This review systematic ally examines the effects of bariatric surgery on drug pharmacokinetics , focusing especially on the mechanisms involved in restricting oral bioavailability .