Intravenous Phytomenadione Administration Technique
Administer phytomenadione 10 mg by slow intravenous infusion over at least 10 minutes (not exceeding 1 mg per minute), diluted in preservative-free 0.9% sodium chloride, 5% dextrose, or 5% dextrose and sodium chloride, with the patient monitored for anaphylactic reactions. 1
Preparation and Dilution
Dilute phytomenadione in preservative-free solutions only: use 0.9% sodium chloride injection, 5% dextrose injection, or 5% dextrose and sodium chloride injection, as benzyl alcohol preservatives are contraindicated. 1
Inspect the solution visually for particulate matter and discoloration prior to administration, and protect from light at all times during preparation and administration. 1
Begin administration immediately after dilution and discard any unused portions of both the diluted solution and the original ampule. 1
Administration Rate and Monitoring
Never exceed 1 mg per minute infusion rate when administering intravenously, meaning a 10 mg dose requires at least 10 minutes of infusion time. 1
Monitor continuously for anaphylactic reactions during and immediately after infusion, as anaphylactoid reactions occur in approximately 3 per 100,000 IV doses and can result in cardiac arrest, severe hypotension, bradycardia/tachycardia, dyspnea, and bronchospasm. 2
The recommended infusion time for major bleeding scenarios is over 30 minutes for the 5-10 mg dose range, which provides an even safer administration rate than the minimum requirement. 2, 3
Clinical Context for 10 mg Dosing
The 10 mg IV dose is reserved exclusively for life-threatening bleeding in combination with 4-factor prothrombin complex concentrate (PCC), not for routine INR correction. 2, 3
For major (non-life-threatening) bleeding, the appropriate dose is 5-10 mg IV, while for INR >10 without bleeding, only 5 mg oral vitamin K is recommended. 2, 3
Co-administration with PCC is mandatory in life-threatening bleeding because factor VII in PCC has only a 6-hour half-life, requiring vitamin K to stimulate endogenous production of vitamin K-dependent clotting factors. 2, 3
Route Selection Hierarchy
Subcutaneous administration is preferred over IV when possible, as the FDA label states "whenever possible, Vitamin K1 Injection should be given by the subcutaneous route" and IV administration should only be used "when considered unavoidable." 1
Oral administration is superior to IV for non-emergency situations due to predictable effectiveness (95% of patients show INR reduction within 24 hours) and significantly lower risk of anaphylactic reactions. 2, 4, 5
IV route achieves faster partial correction than subcutaneous: 44% of IV patients reach INR ≤2 within 12 hours versus only 14% with oral administration, though this speed advantage comes with increased anaphylaxis risk. 2
Critical Safety Considerations
Anaphylaxis risk is non-IgE mediated, likely due to the polyoxyethylated castor oil solubilizer rather than vitamin K itself, making it unpredictable even in patients without prior reactions. 2
Have resuscitation equipment immediately available during IV administration, including epinephrine, antihistamines, and airway management supplies. 2
Do not exceed 10 mg total dose, as higher doses create a prothrombotic state and cause warfarin resistance lasting up to one week, requiring heparin bridging if re-anticoagulation is needed. 2, 3
Post-Administration Monitoring
Recheck INR 15-60 minutes after administration when given with PCC to assess degree of correction, targeting INR <1.5 for surgical hemostasis. 2
Monitor INR serially every 6-8 hours for the first 24-48 hours, as some patients require over a week to clear warfarin and may need additional vitamin K doses. 2
Consider thromboprophylaxis as early as possible after bleeding control is achieved, as PCC use significantly increases thrombotic risk during the recovery period. 2, 3
Common Pitfalls to Avoid
Never administer IV vitamin K as a rapid push or bolus, as this dramatically increases anaphylaxis risk; always use slow infusion over at least 10 minutes. 1
Do not use preserved diluents, as benzyl alcohol toxicity is a serious concern, particularly in vulnerable populations. 1
Avoid using 10 mg IV vitamin K for non-life-threatening scenarios, as this dose is excessive for INR correction without active major bleeding and causes prolonged warfarin resistance. 2, 3
Do not rely on vitamin K alone for emergent reversal, as it takes hours to achieve effect; PCC achieves INR correction within 5-15 minutes and is mandatory for life-threatening bleeding. 2, 3