Vitamin K Dosing Recommendations
Introduction to Vitamin K Prophylaxis
- The American Academy of Pediatrics recommends that all newborns should receive a single intramuscular dose of 0.5 to 1.0 mg vitamin K1 within one hour of birth, as this is the most effective route for preventing all forms of vitamin K deficiency bleeding 1
Newborns
- A single IM dose of 0.5-1.0 mg at birth is the gold standard and most reliable method to prevent early, classic, and late vitamin K deficiency bleeding (VKDB) 1
- The initial dose must be given within one hour of birth 1
Preterm Infants
Oral Administration
- If parents refuse intramuscular administration, an oral regimen of 2 mg at birth, 2 mg at 4-6 days, and 2 mg at 4-6 weeks can be used 2
- Another oral option is 2 mg at birth, then weekly 1 mg doses for 3 months (12 weeks total) 2
High-Risk Newborns
- For infants at elevated risk, the initial dose must be given IM or slow IV 2
Adults
- For adults requiring vitamin K supplementation, the dose ranges from 2.5 to 10 mg for most indications, with higher doses (up to 25-50 mg) reserved for severe deficiency or anticoagulant reversal 1
- The recommended daily supplementation dose is 1-10 mg/day depending on age and risk factors 4
Special Populations
- Infants with cystic fibrosis require 0.3-1.0 mg/day of vitamin K1 4
- Exclusively breastfed infants must receive prophylaxis at birth and continued supplementation if oral route chosen 4, 2
Monitoring
- PIVKA-II (undercarboxylated vitamin K-dependent proteins) is the preferred biomarker for at-risk patients when available 2, 3
- Prompt PT shortening within 2-4 hours after vitamin K administration is diagnostic of VKDB 2
Safety
- Vitamin K1 (phylloquinone) has no known adverse effects or toxicity concerns with supplementation 4, 2
Guidelines for Intramuscular Vitamin K Use in Warfarin Reversal and Emergency Settings
Warfarin Reversal with Major or Life‑Threatening Bleeding
- When rapid reversal of warfarin is required, administer prothrombin complex concentrate (PCC) at 25 IU/kg in conjunction with vitamin K – this combination provides immediate correction of coagulation deficits. 5
- Because factor VII has a short half‑life (~6 h), give vitamin K 5–10 mg intravenously after PCC to sustain clotting factor levels once the PCC effect wanes. 5
- PCC restores normal INR within 10–30 minutes, whereas intravenous vitamin K requires 6–12 hours (or 24 hours orally) to achieve its maximal effect. 5
- Check INR 30 minutes after PCC administration and adjust further dosing based on clinical assessment and repeat laboratory results. 5
Emergency Stocking and Dosing in Hospital Settings
- Facilities should keep a total stock of 50–100 mg of vitamin K for emergency use. 6
- The initial emergency dose should be given intravenously (not exceeding 10 mg); subsequent doses may be administered orally. 6
- In patients with an elevated INR who are actively bleeding, co‑administration of PCC is recommended alongside vitamin K. 6
Interaction with Vitamin E
- High‑dose vitamin E supplementation can worsen vitamin K deficiency and impair coagulation, potentially increasing bleeding risk. 7