Phytonadione and the clotting process -2
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 available.
  • 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 liver.
  • Phytonadione refers to a branch of Vitamin K which is a
    Fat-soluble vitamin'Fat-soluble vitamin is a vitamin that can dissolve in dietary fats. They are stored in body fat.the fat-soluble vitamins are A,D,E and K.'
     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 liver, very little accumulates in tissues, it is metabolized to more polar metabolites and is excreted in bile and urine as glucuronide and sulphate conjugates.
Care must be taken with IV injections of Vitamin K, since they can cause facial flushing, excessive perspirations, chest tightness,
Cyanosis'Cyanosis is a blue coloration of the skin and mucous membranes due to the presence of deoxygenated hemoglobin in blood vessels near the skin surface. It occurs when the oxygen saturation of arterial blood falls below 85-90% (1.5g/dl deoxyhemoglobin)'
, vascular collapse, and shock as well as anaphylaxis.


  • Anticoagulant-induced prothrombin deficiency.
  • Hypo-prothrombinemia due to other causes as that due to salicylates or antibiotics.
  • Hypo-prothrombinemia secondary to factors limiting absorption or synthesis of vitamin K1 .

The Phytonadione dose:

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 be repeated.
  • 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 these drugs.

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  Phytonadione therapy in case of excessive bleeding in newborn or patients with anticoagulant - induced Prothrombin Deficiency.
Heparin: a highly-sulfated glycosaminoglycan, is widely used as an injectable anticoagulant and has the highest negative charge density of any known biological molecule.
 should be used in case of Phytonadione over dosage .