Finally, just as warfarin has many complications in keeping the INR between 2 and 3, the NOACs require consideration of careful dosing differences.

For example, with DVT or PE, using rivaroxaban means a dose of 15 mg twice daily for 21 days (3 weeks), 20 mg once-a-day, providing the patient’s renal function is >50 mL/min.  For AFib the dose with rivaroxaban is 20 mg once-a-day from initiation -- so, an important difference to remember.  Similarly with apixaban for DVT or PE: here apixaban begins as 10 mg twice daily for 7 days, then continues as 5 mg twice daily, which is the standard AFib dose.  These dose escalations in DVT or PE are necessary in case individuals come in with multiple indications, which is actually not that infrequent.

For the DTI dabigatran, on the other hand, the dose from initiation will be the same 150 mg twice daily dose as it is for AFib.  It is also important to remember in the United States the 110 dose is not approved or available.  It is also important to note that dabigatran was studied with a lead-in with injectable anticoagulant heparin first for ≥5 days. 

Finally with the third factor Xa inhibitor, edoxaban, which has yet to be approved in the United States, another difference: 60 mg once a day, the same as the AFib dose, from initiation of therapy, but again, as with dabigatran this drug was studied with a lead-in with injectable heparin.