Answer
Levothyroxine increases warfarin's anticoagulant effect, so the warfarin dose may need to be reduced to avoid excessive anticoagulation, hypoprothrombinaemia and bleeding.
Sources for this answer
- Levothyroxine 25 micrograms TabletsWockhardt UK Ltd · emc · SmPC §4.5 Interaction with other medicinal products · Version 11Document updated
Sources checked