MEPHYTON phytonadione tablet

Country: United States

Language: English

Source: NLM (National Library of Medicine)

Active ingredient:

phytonadione (UNII: A034SE7857) (phytonadione - UNII:A034SE7857)

Available from:

KAISER FOUNDATION HOSPITALS

INN (International Name):

phytonadione

Composition:

phytonadione 5 mg

Prescription type:

PRESCRIPTION DRUG

Authorization status:

New Drug Application

Summary of Product characteristics

MEPHYTON- PHYTONADIONE TABLET
KAISER FOUNDATION HOSPITALS
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TABLETS
MEPHYTON
(PHYTONADIONE)
VITAMIN K
DESCRIPTION
Phytonadione is a vitamin which is a clear, yellow to amber, viscous,
and nearly odorless liquid. It is
insoluble in water, soluble in chloroform and slightly soluble in
ethanol. It has a molecular weight of
450.70.
Phytonadione is 2-methyl-3-phytyl-1, 4-naphthoquinone. Its empirical
formula is C
H O and its
structural formula is:
MEPHYTON (Phytonadione) tablets containing 5 mg of phytonadione are
yellow, compressed tablets,
scored on one side. Inactive ingredients are acacia, calcium
phosphate, colloidal silicon dioxide,
lactose, magnesium stearate, starch, and talc.
1
CLINICAL PHARMACOLOGY
MEPHYTON tablets possess the same type and degree of activity as does
naturally-occurring vitamin
K, which is necessary for the production via the liver of active
prothrombin (factor II), proconvertin
(factor VII), plasma thromboplastin component (factor IX), and Stuart
factor (factor X). The prothrombin
test is sensitive to the levels of three of these four factors – II,
VII, and X. Vitamin K is an essential
cofactor for a microsomal enzyme that catalyzes the posttranslational
carboxylation of multiple,
specific, peptidebound glutamic acid residues in inactive hepatic
precursors of factors II, VII, IX, and
X. The resulting gammacarboxyglutamic acid residues convert the
precursors into active coagulation
factors that are subsequently secreted by liver cells into the blood.
Oral phytonadione is adequately absorbed from the gastrointestinal
tract only if bile salts are present.
After absorption, phytonadione is initially concentrated in the liver,
but the concentration declines
rapidly. Very little vitamin K accumulates in tissues. Little is known
about the metabolic fate of vitamin
K. Almost no free unmetabolized vitamin K appears in bile or urine.
In normal animals and humans, phytonadione is virtually devoid of
pharmacodynamic activity. However,
in animals and humans deficient in vitamin K, the pharmac