A client is started on warfarin therapy while still receiving intravenous heparin. The client questions the nurse about the risk for bleeding. How should the nurse respond?

• A. "Your concern is valid. I will call the doctor to discontinue the heparin."
• B. "It usually takes about 3 days to achieve a therapeutic effect for warfarin, so the heparin is continued until the warfarin is therapeutic."
• C. "Because of your valve replacement, it is especially important for you to be anticoagulated. The heparin and warfarin together are more effective than one alone."
• D. "Because you are now up and walking, you have a higher risk of blood clots and therefore need to be on both medications."

Answer: (B)

The idea being tested is bridging anticoagulation when starting warfarin. Warfarin takes several days to become therapeutic because it gradually depletes the vitamin K–dependent clotting factors, so its effect isn’t immediate. To maintain protection against clotting during that delay, a fast-acting anticoagulant like heparin is continued for about 3 days until warfarin reaches therapeutic levels (as shown by an appropriate INR). This approach prevents a gap in anticoagulation, which is especially important in patients with mechanical valve replacements. Bleeding risk persists with both drugs, but stopping heparin too soon would raise the risk of thrombosis; keeping heparin until warfarin is therapeutic and then stopping heparin is the standard plan. Monitor for signs of bleeding and adjust therapy as needed.