OBJECTIVES AND BACKGROUND: Rivaroxaban, an oral direct factor Xa-inhibitor was 
non-inferior to adjusted dose warfarin in the prevention of stroke and embolism 
among patients with atrial fibrillation (AF) in the ROCKET-AF trial and has been 
approved for stroke prevention in AF.
CASE REPORT: A 88-years-old female (body-mass-index = 19.95) with AF, 
hypertension and diabetes mellitus, hospitalized because of heart failure and a 
non-convulsive epileptic state, was treated by valproate, mirtazepin, nebivolol, 
digitoxin, lisinopril, gliclazide and amlodipine. Irrespective of renal 
insufficiency, rivaroxaban 15 mg/d was started. After 3 days rivaroxaban was 
stopped because of concerns about the bleeding risk. Coagulation tests 28 h 
after rivaroxaban-intake showed INR 2.26, PT 35%, aPTT 38.3 s and anti-Factor 
Xa-activity 2.00 U/ml. Explanations for the prolonged anticoagulant activity of 
rivaroxaban comprise renal failure, the low body-mass-index, the advanced age 
and drug-drug interactions of rivaroxaban with mirtazepin, valproate and 
amlodipine.
CONCLUSION: Health care providers should consider renal function, concomitant 
medication, polymorbidity and age prior to prescribing rivaroxaban. Care has to 
be taken when prescribing rivaroxaban to patients who are different from those 
included in the ROCKET AF trial.