Why should heparin therapy be continued until warfarin reaches therapeutic levels?

Why should heparin therapy be continued until warfarin reaches therapeutic levels?

• A. Warfarin takes several days to reach therapeutic effect, so heparin is continued until warfarin is therapeutic
• B. Heparin has quicker action but short action
• C. Both
• D. Because of lab monitoring

Answer: (A)

The key idea is bridging anticoagulation. Warfarin doesn’t provide full anticoagulation right away because it lowers the production of vitamin K–dependent clotting factors, and it typically takes several days to reach a therapeutic effect (as shown by the target INR). Heparin acts quickly and has a short duration, so it covers the gap while warfarin’s effect is developing. That’s why heparin is continued until warfarin reaches therapeutic levels, at which point warfarin alone can provide adequate anticoagulation. Monitoring confirms when the INR is in the therapeutic range, guiding when to stop heparin.

The key idea is bridging anticoagulation. Warfarin doesn’t provide full anticoagulation right away because it lowers the production of vitamin K–dependent clotting factors, and it typically takes several days to reach a therapeutic effect (as shown by the target INR). Heparin acts quickly and has a short duration, so it covers the gap while warfarin’s effect is developing. That’s why heparin is continued until warfarin reaches therapeutic levels, at which point warfarin alone can provide adequate anticoagulation. Monitoring confirms when the INR is in the therapeutic range, guiding when to stop heparin.