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An immediate coagulant effect should not be expected after administration of phytonadione.
When vitamin K1 is used to correct excessive anticoagulant-induced hypoprothrombinemia, anticoagulant therapy still being indicated, the patient is again faced with the clotting hazards existing prior to starting the anticoagulant therapy. Phytonadione is not a clotting agent, but overzealous therapy with vitamin K1 may restore conditions which 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. Failure to respond to vitamin K may indicate a congenital coagulation defect or that the condition being treated is unresponsive to vitamin K.
Vitamin K1 is fairly rapidly degraded by light; therefore, always protect MEPHYTON (phytonadione) from light. Store MEPHYTON (phytonadione) in closed original carton until contents have been used. (See also HOW SUPPLIED, Storage.)
Carcinogenesis, Mutagenesis, Impairment of Fertility
Studies of carcinogenicity or impairment of fertility have not been performed with MEPHYTON (phytonadione) . MEPHYTON (phytonadione) at concentrations up to 2000 mcg/plate with or without metabolic activation, was negative in the Ames microbial mutagen test.
Pregnancy Category C: Animal reproduction studies have not been conducted with MEPHYTON (phytonadione) . It is also not known whether MEPHYTON (phytonadione) can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. MEPHYTON (phytonadione) should be given to a pregnant woman only if clearly needed.
Safety and effectiveness in pediatric patients have not been established with MEPHYTON (phytonadione) . Hemolysis, jaundice, and hyperbilirubinemia in newborns, particularly in premature infants, have been reported with vitamin K.
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 (phytonadione) is administered to a nursing woman.
Clinical studies of MEPHYTON (phytonadione) 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.
Last reviewed on RxList: 12/2/2008
This monograph has been modified to include the generic and brand name in many instances.
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