Comparison of injectable and oral anticoagulants
Anticoagulation therapy is commonly administered to residents living in long-term-care communities. In the past, warfarin was the only oral anticoagulant available; however, equally effective therapies have been developed in recent years that offer practitioners and patients more options. Patients who are stable on warfarin therapy may not want to consider switching, but the newer therapies – although more costly – have some advantages over warfarin that may be appealing.
When selecting an anticoagulant, factors that should be considered include:
- Lab monitoring. Unlike warfarin, which requires regular International Normalised Ratio (INR) monitoring,5 the newer agents do not require routine monitoring. However, because many of the newer agents require dose adjustments for use with renal impairment, an initial evaluation of renal function is warranted.
- Antidote. The effects of warfarin can be reversed with Vitamin K.5 Protamine can reverse the anticoagulant effects of low-molecular-weight heparin (LMWH) and heparin (partial reversal).2,4 There is no antidote available to reverse the effects of apixaban, fondaparinux, or rivaroxaban.
- Drug interactions. Most of the new agents are involved in some drug interactions; however, warfarin also has many drug interactions to consider.
- The effect of food. Warfarin may be taken with or without food; however, efficacy can be impacted by foods rich in Vitamin K.5 Cranberry juice can also increase INR.5 Although rivaroxaban 10mg tablets can be taken with or without food, 15mg and 20mg doses should be taken with food.6 Apixaban may be taken with or without food, but grapefruit juice can cause levels to increase.7
- Frequency of administration. Apixaban is dosed twice daily. All other agents are approved for once-daily dosing. It is important to note that rivaroxaban is administered twice daily for initial treatment (three weeks) of DVT/PE. Enoxaparin injection is indicated for once- or twice-daily administration.
- Prosthetic heart valves. Apixaban and rivaroxaban are not recommended for use in patients who have prosthetic heart valves.6,7
- Renal dosing. All of the agents listed below, with the exception of warfarin and heparin, have precautions for use with renal impairment.
The following chart provides a summary of select prescribing information for commonly-prescribed oral and injectable anticoagulants, including the indication, dosing, route of administration, and relative cost.