vitamin K1 (phytonadione) (Vitamin K, Mephyton, AquaMephyton)

Dosing and uses of Vitamin K, Mephyton (vitamin K1 (phytonadione))

• Adult
• Pediatric

 

Adult dosage forms and strengths

tablet

• 100mcg
• 5mg

injection emulsion

• 2mg/mL
• 10mg/mL

 

Nutritional Supplementation

Recommended daily intake (RDA)

Males: 120 mcg/day PO

Females: 90 mcg/day PO

 

Hypoprothrombinemia Due To Drugs or Factors Limiting Absorption or Synthesis

2.5-10 mg PO/IV/IM/SC; may be increased PRN to 25 mg or, rarely, to 50 mg; may be repeated in 12-48 hours

 

Reversal of Warfarin Effects

Omit 1-2 doses, or hold warfarin; monitor INR and adjust warfarin dose accordingly

INR 4.5-10, no bleeding: 2012 ACCP guidelines suggest against routine use; 2008 ACCP guidelines suggest considering vitamin K1 (phytonadione) 1-2.5 mg PO once

INR >10, no bleeding: 2012 ACCP guidelines recommend vitamin K1 PO (dose not specified); 2008 ACCP guidelines suggest 2.5-5 mg PO once; INR reduction observed within 24-48 hr, monitor INR and give additional vitamin K if needed

Minor bleeding, any elevated INR: Consider 2.5-5 mg PO once; may repeat if needed after 24 hr

Major bleeding, any elevated INR: 2012 ACCP guidelines recommend prothrombin complex concentrate, human (PCC, Kcentra) plus vitamin K1 5-10 mg IV (dilute in 50 mL IV fluid and infuse over 20 min)

NOTE: High vitamin K doses (ie, 10 mg or more) may cause warfarin resistance for a week or more; consider using heparin, LMWH, or direct thrombin inhibitors to provide adequate thrombosis prophylaxis in clinical conditions requiring chronic anticoagulation therapy (eg, atrial fibrillation)

 

Dosing Considerations

PO dose may be repeated in 12-48 hr and SC/IV/IM dose in 6-8 hr if necessary

IV rate not to exceed 1 mg/min

Use of high vitamin K doses (10-15 mg) may cause warfarin resistance for ≥1 week

 

Pediatric dosage forms and strengths

tablet

• 100mcg
• 5mg

injection emulsion

• 2mg/mL
• 10mg/mL

 

Nutritional Supplementation

RDA

0-6 months: 2 mcg/day

6-12 months: 2.5 mcg/day

1-3 years: 30 mcg/day

4-8 years: 55 mcg/day

9-13 years: 60 mcg/day

14-18 years: 75 mcg/day

 

Hemorrhagic Disease of the Newborn

Prophylaxis: 0.5-1 mg IM within 1 hr of birth

Treatment: 1 mg/dose/day SC; my require higher doses if mother has been receiving oral anticoagulants

 

Vitamin K, Mephyton (vitamin K1 (phytonadione)) adverse (side) effects

Frequency not defined

Anaphylaxis with too-rapid IV administration (has resulted in death)

Dyspnea

Cyanosis

Erythematous skin eruptions

Pruritus

Scleroderma-like lesions

Flushing

Hyperbilirubinemia (in premature neonates)

Hypotension

Injection site reactions

Taste alterations

 

Warnings

Black box warnings

Severe reactions, including fatalities, have occurred during and immediately after IV administration, even when precautions have been taken with proper dilution and avoidance of rapid infusion

Severe reactions also reported after IM administration; typically, these severe reactions involve hypersensitivity or anaphylaxis and include shock and cardiac or respiratory arrest

IV/IM reactions may occur with first dose (no prior exposure to phytonadione)

Restrict use of IV/IM routes to situations where SC administration is not feasible and serious risk involved is considered justified

 

Contraindications

Hypersensitivity

 

Cautions

Rapid IV administration may cause potentially fatal anaphylaxis

Protect from light; agent is rapidly degraded

Avoid IM route if patients is bleeding or in 3rd trimester of pregnancy

Administer phtonadione to quickly lower INR into safe range in patients receiving vitamin K antagonists

Other forms of vitamin K (eg, menadione) are not effective in these settings; only vitamin K1 (ie, phytonadione) should be used

Time of onset depends on rate of synthesis of clotting factors

Potential for overcorrection

Inefective in hereditary hypoprothrombinemia

Longer treatment durations (up to months) and much higher doses required in patients exposed to long-acting anticoagulant rodenticide

Hemolysis, hyperbilirubinemia, and jaundice reported in newborns treated with larger than recommended doses; use caution

 

Pregnancy and lactation

Pregnancy category: C

Lactation: Excreted in breast milk; use caution

 

Pregnancy categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

 

Pharmacology of Vitamin K, Mephyton (vitamin K1 (phytonadione))

Mechanism of action

Promotes hepatic synthesis of clotting factors II, VII, IX, X (exact mechanism is unknown)

 

Pharmacokinetics

Onset: 6-10 hr (PO); 1-2 hr (IV)

Peak effect: 24-48 hr (PO); 12-14 hr (IV)

 

Metabolism

Metabolized in liver

 

Elimination

Excretion: Urine, feces

 

Administration

IV Administration

Dilute in preservative-free NS, D5W, or D5NS and infuse slowly; infusion rate not to exceed 1 mg/min

IV route should be used only if administration by another route is not feasible

 

Storage

Protect injection emulsion from light at all times

May be autoclaved