Aim of this clinical Trial is the assessment of rivaroxaban PK/PD parameters in patients 6-8 months after bariatric surgery

Weight loss after bariatric surgery can putatively alter drug disposition of rivaroxaban. This may be due to an altered intestinal adaptations several months after the surgical procedure. The aim of this clinical trial is to investigate pharmacokinetic and pharmacodynamic parameters after single application of 10 mg rivaroxaban in patients with prior bariatric intervention (Roux-en-y-gastric bypass or sleeve gastrectomy 6-8 months ago). PK/PD parameters will be assessed during 12 hours after application of rivaroxaban.

Inclusion Criteria:

• Patient with past elective bariatric surgery (Roux-en-Y gastric bypass surgery or sleeve gastrectomy 6-8 months ago)
• Patient aged 18 years and older
• BMI ≥ 35 kg/m2
• Women of child-bearing age: Willingness of using a double barrier contraception method during the study
• Written, informed consent

Exclusion Criteria:

• Intake of oral anticoagulants (phenprocoumon, acenocoumarol, dabigatran, etexilate, apixaban etc.) 4 weeks prior to inclusion in the study
• Application of parenteral anticoagulants (unfractionated heparin, low molecular weight heparins, heparin derivates (fondaparinux etc.) 4 weeks prior to inclusion in the study
• Pharmacologic platelet inhibition 4 weeks prior to inclusion in the study
• Known coagulation disorders (e.g. Willebrand's disease, haemophilia)
• Evidence for deep vein thrombosis or pulmonary embolism in the personal history or in the history of first degree relatives
• Medical condition that is associated with an increased risk for VTE, i.e. active cancer disease, lupus erythematodes chronic inflammatory bowel disease
• Active, clinically significant bleeding
• Congenital or acquired bleeding disorder
• Uncontrolled severe hypertension
• Active gastrointestinal disease that can potentially lead to bleeding disorder: oesophagitis, gastritis, gastroesophageal reflux disease, chronic inflammatory bowel disease
• Vascular retinopathy
• Bronchiectasis or history of pulmonary bleeding
• Prior stroke or TIA
• Hereditary galactose intolerance, Lapp lactase deficiency, glucose-lactose malabsorption
• Severe renal impairment with a creatinine clearance (GFR) of < 30ml/min
• Positive pregnancy test, pregnancy or nursing women
• High risk of bleeding (e.g. active ulcerative gastrointestinal disease)
• Known intolerance of the study medication rivaroxaban
• Concomitant treatment with strong CYP3A4 inhibitors (e.g. ketoconazole, itraconazole, lopinavir, ritonavir, indinavir)
• Concomitant treatment with an P-glycoprotein inhibitor and weak or moderate CYP3A4 inhibitor (e.g. erythromycin, azithromycin, diltiazem, verapamil, quinidine, ranolazine, dronedarone, amiodarone, felodipine)