ASK DIS: Rationale for Oral Vitamin K (Paeds)

Friday, June 19, 2015

Background

Vitamin K is necessary for synthesis of factors II (prothrombin), VII, IX, and X
Vitamin K is undetectable in cord blood
Lactobacillus (primary gut flora in breastfed babies) does not synthesize vitamin K
Breastmilk contains only small amounts of vitamin K (1 – 9 mcg/L); formula (53-66 mcg/L)

Oral Regimens

there is no licensed PO form in US, but parental form can be given orally
in countries that have gone to PO prophylaxis, failures (even with good compliance) have been reported . Failures have not been reported with IM prophylaxis.
since multiple doses are required, compliance is an issue
advise parents regarding the increased risk of VKDB (exact numbers are unknown)
maternal dietary changes have little effect on overall vitamin K status of newborn
maternal vitamin K supplements of 5mg/day (800% RDA) has been shown in one study to raise infant serum levels to near formula-fed levels, but there is no FDA approved MVI that contains this amount of vitamin K

Absorption and Dose:

No specific recommendation on long term prophylactic dose of Vitamin K
oral administration vitamin K1 is absorbed from the small intestine.
The systemic availability following oral dosing is approximately 50%, with a wide range of interindividual variability. Absorption is limited in the absence of bile.
2.5 to 5 mg orally once every 24 hours
Product leaflet recommends similar dose as per IM as the onset of action of action is approximately same for both the route
In terms of absorption, response to oral phytonadione is only slightly slower than response to the intravenous form
neonatal liver disease/ billiary atresia : 1mg OD

References:

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