Medically reviewed by Drugs.com. Last updated on Nov 23, 2023.
2.1 Dosing Considerations
Whenever possible, administer Phytonadione by the subcutaneous route [see WARNING — HYPERSENSITIVITY REACTIONS WITH INTRAVENOUS AND INTRAMUSCULAR USE]. When intravenous administration is unavoidable, inject the drug very slowly, not exceeding 1 mg per minute [see WARNINGS AND PRECAUTIONS (5.1)].
Monitor international normalized ratio (INR) regularly and as clinical conditions indicate. Use the lowest effective dose of Phytonadione.
The coagulant effects of Phytonadione are not immediate; improvement of INR may take 1-8 hours. Interim use of whole blood or component therapy may also be necessary if bleeding is severe.
When Phytonadione is used to correct excessive anticoagulant-induced hypoprothrombinemia, anticoagulant therapy still being indicated, the patient is again faced with the clotting hazards existing prior to starting the anticoagulant therapy. Phytonadione is not a clotting agent, but overzealous therapy with Phytonadione may restore conditions which originally permitted thromboembolic phenomena. Dosage should be kept as low as possible, and INR should be checked regularly as clinical conditions indicate.
2.2 Recommended Dosage for Coagulation Disorders from Vitamin K Deficiency or Interference
The recommended dosage of Phytonadione is based on whether the hypoprothrombinemia is anticoagulant-induced (e.g., due to coumarin or indanedione derivatives) or non-anticoagulant-induced (e.g., due to antibiotics; salicylates or other drugs; factors limiting absorption or synthesis) as follows:
- Anticoagulant-Induced Hypoprothrombinemia: Phytonadione 2.5 mg to 10 mg or more subcutaneously, intramuscularly, or intravenously. Up to 25 mg to 50 mg may be administered as a single dose.
Repeated large doses of Phytonadione are not warranted in liver disease if the initial response is unsatisfactory. Failure to respond to Phytonadione may indicate that the condition being treated is inherently unresponsive to Phytonadione.
- Hypoprothrombinemia Due to Other Causes(Non-Anticoagulation-Induced Hypoprothrombinemia): Phytonadione 2.5 mg to 25 mg or more intravenously, intramuscularly, or subcutaneously. Up to 50 mg may be administered as a single dose.
Evaluate INR after 6-8 hours, and repeat dose if INR remains prolonged. Modify subsequent dosage (amount and frequency) based on the INR or clinical condition.
2.3 Recommended Dosage for Prophylaxis and Therapy of Vitamin K Deficiency Bleeding in Neonates
Prophylaxis of Vitamin K-Deficiency Bleeding in Neonates
The recommended dosage of Phytonadione is 0.5 mg to 1 mg within one hour of birth for a single dose.
Treatment of Vitamin K Deficiency Bleeding in Neonates
The recommended dosage of Phytonadione is 1 mg given either subcutaneously or intramuscularly. Consider higher doses if the mother has been receiving oral anticoagulants.
A failure to respond (shortening of the INR in 2 to 4 hours) may indicated another diagnosis or coagulation disorder.
2.4 Directions for Dilution
Dilute Phytonadione with 0.9% Sodium Chloride Injection, 5% Dextrose Injection, or 5% Dextrose and Sodium Chloride Injection. Avoid use of other diluents that may contain benzyl alcohol, which can cause serious toxicity in newborns or low birth weight infants [see WARNINGS AND PRECAUTIONS (5.2) and USE IN SPECIFIC POPULATIONS (8.4)].
When diluted start administration of Phytonadione immediately after dilution.
Discard unused portions of diluted solution as well as unused contents of the ampul.
Protect Phytonadione from light at all times.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
More about Aquamephyton (phytonadione)
- Check interactions
- Compare alternatives
- Latest FDA alerts (1)
- Side effects
- During pregnancy
- Drug class: anticoagulant reversal agents
Related treatment guides
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.