by ofonorow ?? Thu Mar 29, 2012 4:41 am I asked Dr. Levy about the Livon warning Special Notes: It is not recommended that any form of vitamin C be taken with blood thinners, such as Coumadin or Warfarin. , and this is his response:Hi Owen, Prothrombin times must be checked more frequently, at least initially, when vitamin C is taken with Coumadin or warfarin, with the doc usually adjusting the