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.