Mephyton (phytonadione 5mg tablets)

Prescribing Information

The only prescription vitamin K tablet available in the US

MEPHYTON® tablets are indicated in:

  • anticoagulant-induced prothrombin deficiency caused by coumarin or indanedione derivatives;
  • hypoprothrombinemia secondary to antibacterial therapy;
  • hypoprothrombinemia secondary to administration of salicylates;
  • hypoprothrombinemia secondary to obstructive jaundice or biliary fistulas but only if bile salts are administered concurrently, since otherwise the oral vitamin K will not be absorbed1

MEPHYTON® acts just like naturally occurring vitamin K, requires bile salts for absorption from the gastrointestinal tract, and generally exerts its effect within 6 to 10 hours.1

American College of Chest Physicians guidelines for managing over-anticoagulation due to vitamin K antagonists recommend oral administration of vitamin K unless rapid reversal of the international normalized ratio (INR) is required.2

Important Safety Information1

  • An immediate coagulant effect should not be expected after administration of phytonadione
  • Phytonadione will not counteract the anticoagulant action of heparin
  • Phytonadione is not a clotting agent, but overzealous therapy with vitamin K1 may restore conditions that originally permitted thromboembolic phenomena
  • Dosage should be kept as low as possible, and prothrombin time should be checked regularly as clinical conditions indicate
  • Repeated large doses of vitamin K are not warranted in liver disease if the response to initial use of the vitamin is unsatisfactory

ADVERSE REACTIONS

Severe hypersensitivity reactions, including anaphylactoid reactions and deaths have been reported following parenteral administration. The majority of these reported events occurred following intravenous administration.

Transient "flushing sensations" and "peculiar" sensations of taste have been observed with parenteral phytonadione, as well as rare instances of dizziness, rapid and weak pulse, profuse sweating, brief hypotension, dyspnea, and cyanosis.

Hyperbilirubinemia has been observed in the newborn following administration of parenteral phytonadione. This has occurred rarely and primarily with doses above those recommended.

References:

  1. MEPHYTON package insert.
  2. Ansell J, Hirsh J, Poller L, et al. The pharmacology and management of the vitamin antagonist: the seventh ACCP conference on antithrombotic and thrombolytic therapy. Chest. 2004;126 (suppl 3):204S-233S [erratum in: Chest. 2005;127:415-416.]