When caring for a patient who has started anticoagulant therapy with warfarin (Coumadin), the nurse knows not to expect therapeutic benefits for.. At least 12 hours

When caring for a patient who has started anticoagulant therapy with warfarin (Coumadin), the nurse knows not to expect therapeutic benefits for:

1. At least 12 hours***
2. The first 24 hours
3. 2-3 days
4. 1 week.