Menatetrenone

Menatetrenone (INN), also known as MK-4, is a vitamin K compound used as a hemostatic agent, and also as adjunctive therapy for the pain of osteoporosis. Menatetrenone is one of the nine forms of vitamin K2. Menatetrenone (INN), also known as MK-4, is a vitamin K compound used as a hemostatic agent, and also as adjunctive therapy for the pain of osteoporosis. Menatetrenone is one of the nine forms of vitamin K2. MK-4 is produced via conversion of vitamin K1 in the body, in the testes, pancreas and arterial walls. While major questions still surround the biochemical pathway for the transformation of vitamin K1 to MK-4, studies demonstrate the conversion is not dependent on gut bacteria, occurring in germ-free rats and in parenterally-administered K1 in rats. In fact, tissues that accumulate high amounts of MK-4 have a remarkable capacity to convert up to 90% of the available K1 into MK-4. Bioavailability studies have shown that small oral doses are not detected in the blood - for example 420mcg of Menatetrenone or less tested over minutes and hours are not detectable, and larger doses in the order of milligrams are required, unlike Vitamin K2 MK7 which is detectable in the blood in mcg doses. Furthermore, as quoted in citation 'Administered daily doses of 15, 45, 90, and 135 mg revealed that 45 mg was the minimum effective dose for improving bone mass parameters evaluated by microdensitometry and/or single photon absorptiometry in postmenopausal women with osteoporosis.' The study referenced is available in Japanese. Briefly, 15mg, 45mg, 90mg, 135mg and a 5th group with 0.75ug of alfacalcidol were evaluated. The counts of people who had a 'moderate improvement' or greater were recorded. The 15mg group had 26.9%, the 45mg 46%, the 90mg 49% and the 135mg had 50.9% of subjects with a moderate improvement or greater.. It was therefore determined that doses above 45mg as much as 135mg have the same effectiveness as 45mg and that 45mg was much better than 15mg. Therefore 45mg was determined to be the ideal dose. MK-4 is marketed for the osteoporosis indication in Japan by Eisai Co., under the trade name Glakay.