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phytonadione; vitamin K1; phylloquinone; phytomenadione; methylphytyl naphthoquinone (Mephyton, AquaMephyton)
Tradnames: Mephyton, AquaMephyton.
Indications:
- coagulation disorders secondary to vitamin K deficiency
- factor II deficiency
- factor VII deficiency
- factor IX deficiency
- factor X deficiency
- hemorrhagic disease of the newborn
- abetalipoproteinemia [7]
- cholestasis [7]
Dosage:
1) 5-10 mg PO/IV/SC/IM BID PRN
2) recheck INR 6-8 hours after parenteral administration or 12-48 hours after oral administration
3) infants & children 1-2 mg every 4-8 hours IM/IV
Tabs: 5 mg.
Injection: 2 mg/mL (0.5 mL), 10 mg/mL (1 mL, 2.5 mL, 5 mL). .Recommended IV dosing to reverse coumadin excess (no bleeding)
1) INR < 6: omit 1-2 doses of coumadin & restart at lower dose when INR is therapeutic
2) INR = 6-10: vit K 0.5-1 mg slow IV/PO; may repeat in 24 hours if INR is still elevated; consider 2.5-5.0 mg orally#
3) INR 10-20: vit K 3-5 mg slow IV*; may repeat in 6-12 hours if INR is still elevated
4) INR > 20: vit K 10 mg slow IV*; may repeat in 12 hours if INR is still elevated
* vit K should be diluted & given not faster than 1 mg/min
# vit K 1.0 mg PO may be more appropriate [4] PO as effective as IV [5]
Injectable vitamin K can be given orally if < 5 mg dose [6]
Pharmacokinetics:
1) only absorbed from the GI tract via intestinal lymphatics in the presence of bile salts
2) little is known about the metabolic fate of vitamin K
3) coagulation factors II, VII, IX & X increase with 6-12 hours after oral administration & within 1-2 hours after parenteral administration
4) following parenteral administration PT may normalize in 12-14 hours
Adverse effects:
1) uncommon (< 1%)
- prolonged PT with high doses, GI distress, hemolysis in patients with G6PD deficiency, pain, sweating, tenderness at site of injection
2) other
- anaphylactoid reactions have occurred, mostly with IV administration
- flushing sensation
- hypotension
Drug interactions:
1) phytonadione antagonizes effect of coumadin
2) mineral oil may decrease absorption of vitamin K
General
vitamin K
Properties
MISC-INFO: elimination route LIVER
pregnancy-category C
safety in lactation ?
Database Correlations
PUBCHEM correlations
References
- The Pharmacological Basis of Therapeutics, 9th ed.
Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- Drug Information & Medication Formulary, Veterans Affairs,
Central California Health Care System, 1st ed., Ravnan et al
eds, 1998
Department of Veterans Affairs, VA National Formulary
- Kaiser Permanente Northern California Regional Drug
Formulary, 1998
- Journal Watch 22(19):150, 2002
Crowther MA et al, Ann Intern Med 137:251, 2002
- Journal Watch 24(1):2, 2004
Lubetsky A et al Arch Intern Med 163:2469, 2003
PMID: 14609783
- Prescriber's Letter 13(10): 2006
Alternative or 'Off-label' Routes of Drug Administration
Detail-Document#: 221012
(subscription needed) http://www.prescribersletter.com
- Deprecated Reference