Phytonadione (Vitamin K1) is an analogue of Vitamin K but it has:
► The quickest onset of action
► The most prolonged duration
► The most potent of all the Vitamin K forms.
► It is also safer than menadione (K3) to use on newborns.
► K3 is the only one that could cause toxicity, causing hemolytic anemia
( happens when the RBC's die more quickly than the body can reproduce.
There is no record that the other two forms have produced toxic levels).
► It speeds liver damage, producing jaundice, deafness, and severe
neurological problems, including retardation in infants.
Anticoagulant rodenticides interfere with the vitamin K-dependent
carboxylation of factors II, VII, IX and X by inhibiting the
epoxide-reductase enzyme necessary for the recycling of
Vitamin K, thus
depleting body stores of Vitamin K. As a result, only nonfunctional
precursors of the vitamin K-dependent factors are synthesized.
Coumarin compounds including warfarin, coumafuryl, brodifacoum, and
bromadiolone have a half-life of up to 55 hours.
In contrast, indanedione compounds (pindone, valone, diphacinone and
chlorophacinone) have a half-life as long as 4 to 5 days and can affect
homeostasis for as long as 30 days.
In addition, the indanedione compounds may interfere with exocrine
pancreatic function resulting in reduced intestinal absorption of
Vitamin K. It is insoluble in water, soluble in chloroform and slightly
soluble in ethanol.
Vitamin K is found in two forms in nature:
► Phytonadione or Vitamin K1 which is found in plants
► Menaquinone or Vitamin K2 which can be synthesized by many bacteria.
A manmade form of Vitamin K called menadione or Vitamin K3 is also
► Besides its blood clotting function, recent medical research has linked
Vitamin K with the prevention of osteoporosis, a disease that weakens
the bones. This is important as calcium was the only known preventative
of this disease.
► Vitamin K is also produced naturally in the intestines where it assists
the conversion of glucose to glycogen which is then stored in the
Phytonadione refers to a branch of Vitamin K which is a
vitamin required for the normal clotting of the blood.
Phytonadione tablets & injection
It possesses the same type and degree of activity as does
naturally-occurring Vitamin K , which is necessary for hepatic
biosynthesis of active prothrombin ( factor II ), proconvertin ( factor
VII ), plasma thromboplastin component ( factor IX ), and Stuart factor
( factor X ) .
Phytonadione is a specific antagonist for coumarin and indanedione and
similar anticoagulants. It is indicated in the prophylaxis and treatment
of hemorrhagic diseases.
Phytonadione is readily absorbed orally and
after injection. After absorption, it accumulates mainly in the
very little accumulates in tissues, it is metabolized to more polar
metabolites and is excreted in bile and urine as glucuronide and
Care must be taken with IV injections of Vitamin K, since they can cause
facial flushing, excessive perspirations, chest tightness,
vascular collapse, and shock as well as anaphylaxis.
► Anticoagulant-induced prothrombin deficiency.
► Hypo-prothrombinemia due to other causes as that due to salicylates or
► Hypo-prothrombinemia secondary to factors limiting absorption or
synthesis of vitamin K1 .
The recommended dosage in newborn infants that are afflicted with
Vitamin K deficiency is a single dose of 5 mg of
Phytonadione. In adults
with Vitamin K deficiency, the recommended dosage of
Phytonadione is 10
mg taken orally per week.
► Hemorrhagic disease of newborn:
Prophylaxis.................. 0.5 - 1 mg IM within 1 hour of birth.
Treatment.....................1 mg SC or IM ( higher doses may be
necessary if mother has been receiving oral anticoagulants ).
► Anticoagulant-Induced Prothrombin Deficiency in Adults (caused by
coumarin or indanedione derivatives) :
2.5 - 10 mg or up to 25 mg initially and rarely up to 50 mg ( orally or
by injection ).
Frequency & amount of subsequent doses should be determined by
prothrombin time response or clinical condition. If in 6 to 8 hours
after injection or 12 to 48 hours after oral administration, the
prothrombin time has not been shortened satisfactorily, the dose should
► Hypo-prothrombinemia due to other causes in Adults ( e.g.
antibiotics, salicylates or other drugs ):
2.5 - 25 mg initially and rarely up to 50 mg ( orally or by injection ).
The severity of the coagulation disorder should determine whether to
discontinue or reduce the dosage of drugs interfering with coagulation
mechanisms ( antibiotics or salicylates ) only or to administer
Phytonadione immediately in addition of discontinuation or reduction of
Phytonadione injection should be injected IM or IV very slowly not
exceeding 1 mg / minute .
Blood or blood component transfusion is required in addition of
therapy in case of excessive bleeding in newborn or patients with
anticoagulant - induced Prothrombin Deficiency.
Heparin should be used in case of Phytonadione over dosage .