VITAMIN K IS AN ESSENTIAL COFACTOR IN THE HEPATIC SYNTHESIS OF PROTHROMBIN (FACTOR II) AND OTHER BLOOD CLOTTING FACTORS (FACTORS VII, IX, AND X, AND PROTEINS C AND S) AND IN THE FUNCTION OF PROTEINS SUCH AS OSTEOCALCIN IMPORTANT FOR BONE DEVELOPMENT.
VITAMIN K DEFICIENCY MAY DEVELOP IN NEONATES, BUT IS UNCOMMON IN ADULTS, ALTHOUGH IT MAY OCCUR IN PATIENTS WITH MALABSORPTION SYNDROMES, OBSTRUCTIVE JAUNDICE OR HEPATIC DISEASE. DEFICIENCY LEADS TO THE DEVELOPMENT OF HYPOPROTHROMBINAEMIA, IN WHICH THE CLOTTING TIME OF THE BLOOD IS PROLONGED AND SPONTANEOUS BLEEDING CAN OCCUR. COUMARIN ANTICOAGULANTS INTERFERE WITH VITAMIN K METABOLISM, AND THEIR EFFECTS CAN BE ANTAGONISED BY GIVING VITAMIN K.
MENADIOL SODIUM PHOSPHATE IS A WATER-SOLUBLE DERIVATIVE OF MENADIONE, A SYNTHETIC LIPID-SOLUBLE VITAMIN K ANALOGUE. IT MAY BE USED FOR THE PREVENTION OF VITAMIN K DEFICIENCY IN PATIENTS WITH MALABSORPTION SYNDROMES IN WHOM ORAL PHYTOMENADIONE MAY BE INEFFICIENTLY ABSORBED. IT IS GIVEN IN USUAL DOSES EQUIVALENT TO 10 TO 40 MG OF MENADIOL PHOSPHATE DAILY BY MOUTH.