Why would a patient receiving IV heparin also be started on warfarin?

The correct choice highlights that warfarin, an oral anticoagulant, does not achieve its therapeutic effect immediately. It typically takes 12 to 24 hours for warfarin to start working, and its full anticoagulant effect may take several days. This delayed onset is significant for patients transitioning from heparin to warfarin because heparin provides immediate anticoagulation due to its rapid onset of action.

Initiating warfarin therapy while a patient is on heparin ensures that the patient is adequately anticoagulated during the period when warfarin is becoming effective, thereby preventing the risk of thromboembolism. The transition is often part of a broader strategy to provide continuous anticoagulation while moving from parenteral (heparin) to oral (warfarin) therapy.

In this context, the other options do not appropriately convey the rationale for the initiation of both medications. Additional medication may not necessarily be required if warfarin were effective immediately. While heparin may have its limitations, it does not follow that warfarin is simply 'more effective' as both medications serve different purposes and mechanisms. The characterization of heparin as having low molecular weight alone does not explain the reason for