Phytonadione (vitamin K)PA study guide
An injectable form of vitamin K1 that helps the liver make clotting factors. It reverses bleeding problems from warfarin-type blood thinners or low vitamin K, and it is given to newborns to prevent bleeding.
An injectable form of vitamin K1 that helps the liver make clotting factors. It reverses bleeding problems from warfarin-type blood thinners or low vitamin K, and it is given to newborns to prevent bleeding.
Labeled use. Coagulation disorders from vitamin K deficiency or interference: coumarin or indanedione anticoagulants, antibiotics, malabsorption, or other drugs such as salicylates.
Sources: [1]
Labeled use. Prophylaxis and treatment in neonates.
Sources: [1]
Phytonadione is the vitamin K replacement used for warfarin reversal and for newborn vitamin K prophylaxis. Because it takes hours to work, life-threatening warfarin bleeding also needs a fast product such as four-factor prothrombin complex concentrate or plasma. Although the label favors subcutaneous use, many reversal protocols give a slow IV infusion for urgent reversal because subcutaneous absorption is less predictable. It does not reverse heparin (protamine), direct oral anticoagulants such as apixaban, or thrombolytics, and oral vitamin K for an elevated INR without bleeding is outside this record's scope.
Vitamin K1 replacement. It is a cofactor for the hepatic microsomal enzyme that carboxylates glutamic acid residues on the inactive precursors of factors II, VII, IX, and X, activating them for secretion. It has almost no activity in people who are not vitamin K deficient. IV: effect detectable within 1 to 2 hours, bleeding usually controlled in 3 to 6 hours, INR often normal in 12 to 14 hours.
The label does not describe a narrow therapeutic index or direct dosing by measured blood levels of the drug. Dosing is guided by the INR, not by phytonadione levels.
Sources: [1]
Doses come from the FDA label. Study tool, not for clinical decisions.
No renal dose adjustment on the label. The product contains aluminum, which can reach toxic levels with prolonged parenteral use when kidney function is impaired.
Sources: [1]
No set adjustment. In liver disease, do not keep repeating large doses after a poor first response; failure to respond may mean the condition cannot respond to vitamin K.
Sources: [1]
IV and IM injection have caused fatal hypersensitivity reactions, including anaphylaxis, during or right after the dose, even when diluted and on the first dose. Give it subcutaneously unless that route is not feasible and the serious risk of IV or IM use is justified.
Sources: [1]
None. Treat hypersensitivity reactions as an emergency, and stop the drug for skin reactions and manage medically. Newborn overdose can cause hemolysis, jaundice, and hyperbilirubinemia. If reversal goes too far while anticoagulation is still needed, heparin still works because phytonadione does not affect it.
Published studies have not shown a clear link to adverse developmental outcomes. Vitamin K deficiency in pregnancy raises maternal bleeding risk at delivery and has been linked to rare fetal intracranial hemorrhage. Use a benzyl alcohol-free formulation if one is available.
Sources: [1]
Phytonadione is present in breast milk; effects on the breastfed infant and on milk production are unknown. Use a preservative-free formulation if available.
Sources: [1]
Established in neonates. Prophylaxis of vitamin K-deficiency bleeding: 0.5 to 1 mg as a single dose within one hour of birth. Treatment: 1 mg SC or IM, higher if the mother took oral anticoagulants; no INR shortening in 2 to 4 hours suggests another diagnosis. Use benzyl alcohol-free products when possible. Not established in children 6 months to 17 years.