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 .
The effect of bariatric surgery on the direct oral anticoagulant rivaroxaban: the extension study.
BACKGROUND Thromboembolic disease is a potentially serious complication in bariatric surgery patients . Direct oral anticoagulants ( DOAC ) have been investigated in orthopedic surgery patients .  DOAC data after bariatric surgery are still limited to the early postsurgical period . Whether postsurgical midterm adaptations due to anatomic and physiologic alterations influence drug pharmacology is currently not known . OBJECTIVE The aim of this study was to investigate the influence of weight loss and type of bariatric surgery on midterm postsurgical pharmacokinetic and pharmacodynamic parameters of rivaroxaban . SETTING University hospital . METHODS In this monocentric study , bariatric patients received a single oral dose of rivaroxaban ( 10 mg ) 6 to 8 months after sleeve gastrectomy ( SG ) or Roux-en-Y-gastric bypass ( RYGB ) . Pharmacokinetic and pharmacodynamic parameters were assessed and compared with prebariatric surgery results . RESULTS We included 6 RYGB and 6 SG patients .  Percent excess weight loss was 71.4 % ( interquartile range 56.4 , 87.9 ) in the SG group and 76.6 % ( 64.5 , 85.7 ) in the RYGB group . Rivaroxaban mean areas under the curve 6 to 8 months after the bariatric procedure ( 922.4 µg × h/L , coefficient of variation 43.2 ) were comparable to those measured preoperatively ( 952.6 µg × h/L , 16.8 ) . There was no relevant difference between the 2 surgical procedure groups . Rivaroxaban led to a decrease of prothrombin fragments F1 + 2 over 12 hours after oral intake confirming in vivo efficacy . CONCLUSIONS Significant weight loss and altered anatomy after RYGB and SG procedures do not appear to affect the pharmacokinetics and pharmacodynamics of prophylactic rivaroxaban . A single dose of Rivaroxaban was well tolerated and considered safe in this trial
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 .