side effects

Last reviewed 09/2023

  • bleeding - dose-related

  • in pregnancy, recommended that only used during the 13th to 36th week because of fetal abnormalities associated with it's use during the first trimester - chondrodysplasia punctata - and after the 36th week - fetal intracerebral bleeding. In instances where anticoagulation is indicated, it is recommended that low molecular weight heparin be used during the first trimester and after 36 weeks because it does not cross the placenta

  • in liver disease, there is a reduced requirement for warfarin because of reduced synthesis of clotting factors. Also if there is obstructive jaundice then there is a reduction in absorption of vitamin K, which in turn reduces the requirement for warfarin

  • in congestive heart failure, warfarin requirement is reduced

  • thyroid disease - requirements for warfarin are increased in thyrotoxicosis, and reduced in hypothyroidism