[Treatment of primary osteoporosis with vitamin K2].

Menatetrenone (MK-4) is a form of vitamin K(2) (VK(2)) which is utilized for the treatment of osteoporosis. MK4 has a grade B as a total recommendation rate in the Japanese guideline for the prevention and treatment of osteoporosis in 2006 based on the current clinical evidences. The effects of fracture prevention by MK-4 are assumed to be based on the increase of bone mineral density as well as the improvement of bone quality. Recent researches suggest that VK affects bone metabolism via nuclear receptor in addition to the carboxylation of VK dependent proteins.