Question

Warfarin therapy is monitored by the international normalization ratio (INR) (target 4 to 5) Select one: True or False

Answer 1

False:

Explanation

• Warfarin is a anticoagulant drug.
• It is a vitamin-k antagonist.
• It reduces the levels of clotting fators - II, VII, IX, X
• The warfarin therapy is monitored by doing international normalised ratio or INR.
• INR is calculated based on the patient's prothrombin time and international senstive index.
• Normally, the INR < 1.1
• The targets for INR dependent on the underlying disease for which warfarin is being given.
• The targets of INR as per the disease is given in the table below.

• Sr.No	Disease	INR target
  1	Mechanical mitral valve replacement	2.5 - 3.5
  2	Other valve replacement	2 - 3
  3	Venous pulmonary thromboembolism	2 - 3
  4	Atrill fibrillation	2 - 3

• When the INR value exceeds 3 the warfarin dose should be reduced.

• If the INR value goes above 4 or 4.5, there is a increase risk of major life-threatening hemorrhage.

• Therefore, INR target of 4 - 5 is not correct. Corrective measures should be taken when the INR value reaches this level.

• Activated prothrombin complex concentrates and Vitamin K are antidotes for warfarin toxicity.