What is the treatment for warfarin overdose?

Stop Coumadin (warfarin) First stop coumadin (warfarin). Avoid trauma. Either wait 2 days or go to hospital for fresh frozen plasma.
Vitamin K. Warfarin (coumadin (warfarin)) works against vitamin k to make your blood clot less easily. Taking vitamin k reverses the effect of the coumadin (warfarin). That is one of the reasons why you have to be careful eating dark green leafy vegetables, like spinach, when you take coumadin (warfarin). Spinach, kale, etc., all contain vitamin k and reduce the effect of coumadin (warfarin).