Phytonadione
(Vitamin K ₁)
Phytonadione (Aqua-Mephyton)
Vitamin K ₁ (Aqua-Mephyton)
Phytonadione
(fye-toe-nah- DYE-ohn)
Pregnancy Category: C Aqua-Mephyton Mephyton (Rx)

Classification: Fat-soluble vitamin

Action/Kinetics: Vitamin K is essential for the hepatic synthesis of factors II, VII, IX, and X, all of which are essential for blood clotting. Vitamin K deficiency causes an increase in bleeding tendency, demonstrated by ecchymoses, epistaxis, hematuria, GI bleeding, and postoperative and intracranial hemorrhage. Phytonadione is similar to natural vitamin K. GI absorption occurs only via intestinal lymphatics and requires the presence of bile salts. Vitamin K is not effective in reversing the anticoagulant effect of heparin. Frequent determinations of PT are indicated during therapy. IM: Onset, 1-2 hr. Control of bleeding: Parenteral, 3-6 hr. Normal PT: 12-14 hr. PO: Onset, 6-12 hr.

Uses: Primary and drug-induced hypoprothrombinemia, especially that caused by anticoagulants of the coumarin and phenindione type. Vitamin K cannot reverse the anticoagulant activity of heparin.
Parenteral use for vitamin K malabsorption syndromes. Adjunct during whole blood transfusions. Preoperatively to prevent the danger of hemorrhages in surgical clients who may require anticoagulant therapy.

Contraindications: Severe liver disease.

Special Concerns: Use with caution in clients with sulfite sensitivity and during lactation as phytonadione is excreted in breast milk. Safety and efficacy have not been determined in children. Benzyl alcohol, contained in some preparations, may cause toxicity in newborns.

Side Effects: May be transient flushing of the face, sweating, a sense of constriction of the chest, and weakness. Cramp-like pain, weak and rapid pulse, convulsive movements, chills and fever, hypotension, cyanosis, or hemoglobinuria has been reported occasionally. Shock and cardiac and respiratory failure may be observed. Allergic: Rash, urticaria, anaphylaxis. After PO use: N&V;, stomach upset, headache. After parenteral use: Flushing, alteration of taste, sweating, hypotension, dizziness, rapid and weak pulse, dyspnea, cyanosis, delayed skin reactions. Pain, swelling, and tenderness at injection site. IV administration may cause severe reactions (e.g., shock, cardiac or respiratory arrest, anaphylaxis) leading to death. These effects may occur when receiving vitamin K for the first time. Newborns: Fatal kernicterus hemolysis, jaundice, hyperbilirubinemia (especially in premature infants).

Drug Interactions: Antibiotics / May inhibit vitamin K production bleeding; give vitamin K supplements Anticoagulants, oral / Antagonizes anticoagulant effect Cholestyramine / Phytonadione effect R/T GI tract absorption Colestipol / Phytonadione effect R/T GI tract absorption Hemolytics / Potential for toxicity Mineral oil / Phytonadione effect R/T GI tract absorption Quinidine, Quinine / Requirement for vitamin K Salicylates / High doses vitamin K requirements Sulfonamides / Requirements for vitamin K Sucralfate / Phytonadione effect R/T GI tract absorption

How Supplied: Injection: 1 mg/0.5 mL, 10 mg /mL; Tablet: 0.1 mg, 5 mg

Dosage
?Tablets Hypoprothrombinemia, drug-induced.
Adults: 2.5-10 mg (up to 25 mg); dose may be repeated after 12-48 hr if needed.
Vitamin supplement, prothrombogenic, drug-induced hypoprothrombinemia.
Pediatric: 5-10 mg.
?IM, SC Vitamin supplement, prothrombogenic, drug-induced hypoprothrombinemia.
Adults: 2.5-10 mg (up to 25 mg) which may be repeated after 6-8 hr if needed. Infants: 1-2 mg; children: 5-10 mg.
Prophylaxis of hypoprothrombinemia during prolonged TPN.
Adults, IM: 5-10 mg once weekly; pediatric: 2-5 mg IM once weekly.
Infants receiving milk substitutes or who are breastfed.
1 mg/month if vitamin K in diet is less than 0.1 mg/L.
Prevention of hemorrhagic disease in the newborn.
0.5-1 mg IM within 1 hr after delivery. The dose may be repeated in 2-3 weeks if the mother took anticoagulant, anticonvulsant, antituberculosis, or recent antibiotic therapy during pregnancy. Alternatively, 1-5 mg given to the mother 12-24 hr before delivery.
Treatment of hemorrhagic disease in the newborn.
1 mg SC or IM (higher doses may be needed if the mother has been taking oral anticoagulants).