The only prescription vitamin K tablet available in the US
Acts just like naturally occurring vitamin K and generally exerts its effect within 6 to 10 hours1
- Adequately absorbed from the GI tract, but only when bile salts are present1
- Initially concentrated in the liver, but concentration declines rapidly1
Indicated for
- Anticoagulant-induced prothrombin deficiency due to coumarin or indanedione derivatives1
- Hypoprothrombinemia secondary to antibacterial therapy1
- Hypoprothrombinemia secondary to administration of salicylates1
- Hypoprothrombinemia secondary to obstructive jaundice or bilary fistulas, but only if bile salts are administered concurrently, since otherwise the oral vitamin K will not be absorbed1
| MEPHYTON® (phytonadione) 5 mg tablets offer distinct advantages over other routes of vitamin K administration unless rapid reversal of INR is required2-4 |
||
|---|---|---|
| Route | Advantages | Disadvantages |
| ORAL (tablet) ACCP recommended route |
Relatively convenient to use | Available in one dose (5-mg scored tablet) |
| Relatively low incidence of anaphylactoid reactions observed | Need for functional GI system
|
|
| Low risk of over-correction | ||
| INTRAVENOUS (IV) Recommended when rapid reversal of INR is required |
Rapid response | requires slow infussion |
| Complete control over dosage | Relatively higher risk for
anaphylasis Risk of over-correction |
|
| May cause facial flushing, diaphoresis, chest pain, hypotension, dyspneam anaphylaxis, and cerebral thrombosis (pretreatment with antihistamines or corticosteroids is not routinely recommended) |
||
| SUBCUTANEOUS (SC) | Lower anaphylaxis risk | Delayed, unpredictable response |
| Risk of cutaneous reactions | ||
| INTRAMUSCULAR (IM) | Vitamin K readily absorbed | Resk of hematoma |
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.
PRECAUTIONS
General
Vitamin K1 is fairly rapidly degraded by light; therefore, always protect MEPHYTON from light. Store MEPHYTON in closed original carton until contents have been used. (See also HOW SUPPLIED, Storage.)
Drug Interactions
Temporary resistance to prothrombin-depressing anticoagulants may result, especially when larger doses of phytonadione are used. If relatively large doses have been employed, it may be necessary when reinstituting anticoagulant therapy to use somewhat larger doses of the prothrombin-depressing anticoagulant, or to use one which acts on a different principle, such as heparin sodium.
Laboratory Tests
Prothrombin time should be checked regularly as clinical conditions indicate.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Studies of carcinogenicity or impairment of fertility have not been performed with MEPHYTON. MEPHYTON at concentrations up to 2000 mcg/plate with or without metabolic activation, was negative in the Ames microbial mutagen test.
Pregnancy
Pregnancy Category C: Animal reproduction studies have not been conducted with MEPHYTON. It is also not known whether MEPHYTON can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. MEPHYTON should be given to a pregnant woman only if clearly needed.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established with MEPHYTON. Hemolysis, jaundice, and hyperbilirubinemia in newborns, particularly in premature infants, have been reported with vitamin K.
Nursing Mothers
It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when MEPHYTON is administered to a nursing woman.
Geriatric Use
Clinical studies of MEPHYTON did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
References:
- MEPHYTON package insert.
- Hanslik T, Prinseau J. The use of vitamin K in patients on anticoagulant therapy: a practical guide. Am J Cardiovasc Drugs. 2004;4:43-55.
- Taylor CT, Chester EA, Byrd DC, Stephens MA. Vitamin K to reverse excessive anticoagulation: a review of the literature. Pharmacother. 1999;19:1415-1425.
- Whitling AM, Bussey HI, Lyons RM. The incidence of anaphylaxis following intravenous phytonadione (vitamin K1): a 5-year retrospective review. Arch Intern Med. 1998;158:2136-2140.
