What is the recommended dose of vitamin K1 (phylomenadione) for newborns?

Vitamin K Dosing for Newborns

The recommended dose of vitamin K1 (phytonadione) for newborns is a single intramuscular injection of 0.5 to 1 mg within one hour of birth. 1, 2

Dosing Recommendations by Route of Administration

Intramuscular Administration (Preferred)

• Intramuscular (IM) route is the preferred method for vitamin K administration due to its efficiency and reliability 2
• Single dose of 0.5 to 1 mg IM within one hour of birth 1
• This is the recommendation from the American Academy of Pediatrics 1, 3
• IM administration provides the most reliable protection against all forms of Vitamin K Deficiency Bleeding (VKDB), including late VKDB 2

Oral Administration (Alternative)

If parents decline IM administration, oral vitamin K may be considered with one of the following regimens:

• 3 × 2 mg vitamin K1 orally at birth, at 4-6 days, and at 4-6 weeks 2
• 2 mg vitamin K1 orally at birth, followed by weekly doses of 1 mg orally for 3 months 2
• If the infant vomits within 1 hour of oral administration, the dose should be repeated 2

Special Populations

Preterm Infants

• Preterm infants on parenteral nutrition should receive 10 μg/kg/day of vitamin K 4, 5
• Oral administration is not appropriate for preterm infants 2

High-Risk Infants

• For infants at high risk of hemorrhage (premature, neonatal disease, birth asphyxia, difficult delivery, delayed feeding, known hepatic disease, maternal drugs interfering with vitamin K), the first dose must be administered IM or by slow intravenous route 6
• Doses may need to be repeated, particularly in premature infants 6

Monitoring

• Classical coagulation tests (PT, PTT) can be used in low-risk infants for indirect evaluation of vitamin K status, though they are not specific to vitamin K deficiency 4, 5
• Undercarboxylated Serum Vitamin K-Dependent Proteins (PIVKA-II) are more useful biomarkers of subclinical vitamin K deficiency for at-risk patients 4, 5

Important Considerations

• All newborn infants should receive vitamin K prophylaxis, and the date, dose, and mode of administration should be documented 2
• Parental refusal after adequate information should be recorded due to the risk of late VKDB 2, 7
• Oral administration is not appropriate for infants who have cholestasis, impaired intestinal absorption, are too unwell to take oral vitamin K1, or whose mothers have taken medications that interfere with vitamin K metabolism 2
• Recent research has not shown any advantage of using a higher 2 mg IM dose compared to the standard 1 mg dose in preventing late-onset VKDB 8

Clinical Pitfalls to Avoid

• Failure to administer vitamin K to all newborns puts them at risk for potentially devastating vitamin K deficiency bleeding 3, 7
• Benzyl alcohol as a preservative in vitamin K preparations has been associated with toxicity in newborns; therefore, preservative-free diluents should be used 1
• Assuming that formula-fed infants don't need vitamin K supplementation (all newborns require prophylaxis regardless of feeding method) 2
• Relying on maternal prenatal vitamin K supplementation alone is insufficient to prevent VKDB in the newborn 6