A nurse is caring for a client who has deep vein thrombosis and has been on heparin continuous infusion for 5 days. The provider prescribes warfarin PO without discontinuing the heparin. The client asks the nurse why both anticoagulants are necessary. Which of the following statements should the nurse make?

A. Heparin and warfarin do not dissolve clots; they prevent new clots from forming and existing clots from growing. B. It would be inappropriate to discontinue heparin before warfarin reaches therapeutic levels, as this could increase the risk of clot progression. C. Heparin does not increase the effect of warfarin; they work via different mechanisms. D. Warfarin takes 3–5 days to reach therapeutic levels. During this period, heparin provides immediate anticoagulation. Both are used concurrently to ensure continuous protection against thrombus formation.