Vitamin K (Phytonadione, Mephyton, AquaMephyton)

Category:

  • Vitamin

Description:

  • Dietary supplement; fat-soluble vitamin

Indications:

  • Vitamin K deficiency

  • Coagulation disorders (blood clotting factors)

  • Anticoagulant-induced prothrombin deficiency

  • Prophylaxis and treatment of hemorrhagic disease in newborn

  • Warfarin overdose antidote

Contraindications:

  • Avoid intravenous administration unless unavoidable.  Administer SQ or IM, if IV must be used give very slowly, not exceeding 1mg per minute.

Precautions:

  • Pregnancy category C

  • Vitamin K deficiency is

  • Patients may develop hypervitaminosis K with excessive intravenous dosages.  Symptoms of hypervitaminosis are “flushing sensations”, taste changes and rarely, dizziness sweating and rapid and weak pulse.

  • Vitamin K will NOT reverse the anticoagulant effects of heparin.

  • Reversal of coumarin class (warfarin) anticoagulation takes from 1-2 hours.

  • Vitamin K is excreted into breast milk.

Adverse Reactions (Side Effects):

Relatively non-toxic in therapeutic doses

Hyperbilirubinemia in newborns, occurring at doses greater than recommended.  

Dosage:

  • Dietary sources: pork, liver, green leafy vegetables (spinach, broccoli), GI flora can produce from diet

  • Administered in oral soft gelatin capsules or injection

  • Dietary supplementation (RDA: recommended daily allowance):

    • Infants: 10-20mcg

    • Children: 15-100mcg

    • Adult males: 45-80 mcg per day

    • Adults females: 45-65 mcg per day

  • Anticoagulant-induced prothrombin deficiency: 2.5-10mg per day (up to 25mg initially)

  • Hemorrhagic disease in newborn:

    • prophylaxis: single IM dose 0.5-1mg within 1 hour of birth, may repeat in 2-3 weeks.  Mother may receive 1-5mg 12-24 hours before delivery.  Oral doses of 2mg are adequate.

    • treatment: 1mg SQ or IM, in conjunction with proper laboratory testing of PT.

  • Hypoprothrombinemia in adults:

    • 2.5-25mg.  Amount and route of administration depends on severity of disease.

 
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