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 .
Pharmacokinetics and pharmacodynamics of single doses of rivaroxaban in obese patients prior to and after bariatric surgery
AIMS Venous thromboembolism is an important cause of postoperative morbidity and mortality in bariatric surgery . Studies of direct oral anticoagulants ( DOACs ) are not available in this surgical field . The objective of this phase 1 clinical trial was to investigate pharmacokinetic and pharmacodynamic ( PK/PD ) parameters of rivaroxaban in bariatric patients . METHODS In this single-centre study , obese patients received single oral doses of rivaroxaban ( 10 mg ) 1 day prior to and 3 days after bariatric surgery . PK and PD parameters were assessed at baseline and during 24 h after drug ingestion . RESULTS Six Roux-en-Y gastric bypass patients and six sleeve gastrectomy patients completed the study .  Mean rivaroxaban area under plasma concentration-time curve , peak plasma concentration , time to peak plasma concentration and terminal half-life were 971.9 μg·h l-1 ( coefficient of variation : 10.6 ) , 135.3 μg l-1 ( 26.7 ) , 1.5 h and 13.1 h ( 34.1 ) prior to and 1165.8 ( 21.9 ) , 170.0 ( 15.9 ) , 1.5 and 8.9 ( 44.6 ) postsurgery for SG patients and 933.7 μg·h l-1 ( 22.3 ) , 136.5 μg l-1 ( 10.7 ) , 1.5 h und 13.8 h ( 46.6 ) prior to and 1029.4 ( 7.4 ) , 110.8 ( 31.8 ) , 2.5 and 15 ( 60.0 ) postsurgery for Roux-en-Y gastric bypass patients , respectively . Prothrombin fragments ( F1 + 2 ) decreased during the first 12 hours and increased thereafter in the pre- and the postbariatric setting . Thrombin-antithrombin complexes dropped within 1 - 3 h in the prebariatric setting and remained low after surgery until they increased at 24 h postdose  . Rivaroxaban was well tolerated and no relevant safety issues were observed . CONCLUSIONS Bariatric surgery does not appear to alter PK of rivaroxaban in a clinical ly relevant way . Effective prophylactic postbariatric anticoagulation is supported by changes in PD
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 .