Short-term treatment for vitamin K deficiency usually involves either oral supplementation or injections. Long-term or lifetime supplementation may be necessary for those with underlying chronic conditions. The action of vitamin K typically requires 2 to 5 days after it is given to show treatment effect.
Problems with high levels of natural forms of vitamin K (K1 and K2) have not been reported. These forms have low toxicity, even at high concentrations. However, water-soluble vitamin K3 can be toxic if administered in large quantities. Also, K3 is known to cause hemolytic anemia in infants, so it is not used to treat the very young.
Vitamin K-dependent clotting factors are produced by the liver. If a person has chronic liver disease, that person may not be able to produce sufficient clotting factors even when adequate vitamin K is available. Vitamin K supplementation may not be effective in those with seriously damaged livers.