What are the VKAs?
The VKAs are a class of OACs; the most commonly used are the 4-hydroxycoumarins and include warfarin, phenprocoumon, and acenocoumarol. Less commonly used VKAs are phenindione and uindione, which are 1,3-indandione derivatives. Geographical variation in VKA popularity is evident, with warfarin commonly used worldwide but acenocoumarol being popular in Spain and phenprocoumon in Germany. In randomized clinical trials, most have used warfarin.