What is the onset of action of K centra (vitamin K)

Onset of Action of Vitamin K (Kcentra)

Intravenous vitamin K begins working within 5-15 minutes, with significant effects on INR seen within 4-6 hours, while oral vitamin K takes 18-24 hours to effectively reverse anticoagulation. 1

Vitamin K Pharmacology and Onset of Action

Vitamin K is a critical cofactor for hepatic production of clotting factors II, VII, IX, and X. When administered for reversal of vitamin K antagonists (VKAs) like warfarin, the onset of action varies significantly based on route of administration:

• Intravenous (IV) administration:

  • Initial effects begin within 5-15 minutes 1
  • Significant INR reduction within 4-6 hours 1
  • Complete effect may take up to 24 hours

• Oral administration:

  • Slower onset of action
  • Takes 18-24 hours for significant INR reduction 1
  • Less predictable absorption compared to IV route

• Subcutaneous administration:

  • Unpredictable onset and effect
  • Not recommended for urgent reversal 1

Kcentra (Prothrombin Complex Concentrate)

It's important to clarify that "Kcentra" specifically refers to a 4-factor prothrombin complex concentrate (4F-PCC), not vitamin K itself. Kcentra contains factors II, VII, IX, and X and is often used alongside vitamin K for rapid reversal of anticoagulation.

• Kcentra (4F-PCC) onset of action:
  • Begins within 5-15 minutes after administration 1
  • Duration of effect is 12-24 hours 1
  • More rapid and reliable than fresh frozen plasma 1

Optimal Reversal Strategy

For patients requiring urgent reversal of VKA anticoagulation:

1. For life-threatening bleeding:

   • Administer 4F-PCC (Kcentra) immediately for rapid effect within minutes
   • Simultaneously administer IV vitamin K (5-10 mg) for sustained reversal 1
   • This combination provides both immediate (PCC) and sustained (vitamin K) reversal

2. For non-urgent reversal:

   • Oral vitamin K alone may be sufficient
   • Dose typically 1-2.5 mg for INR 5.0-9.0
   • Higher dose (5 mg) for INR >10.0 2

Clinical Considerations

• The 2020 ACC guidelines recommend slow IV administration of vitamin K in 25-50 mL normal saline over 15-30 minutes 1
• Anaphylactic reactions with IV vitamin K administration are rare with current preparations 1
• Guideline-concordant administration of both PCC and vitamin K within 8 hours of admission is associated with decreased 7-day mortality in patients with severe bleeding on VKA therapy 3
• For intracranial hemorrhage specifically, rapid reversal with both PCC and vitamin K is particularly important for reducing mortality 3

Practical Application

For emergency reversal of anticoagulation:

• Use 4F-PCC (Kcentra) for immediate effect
• Add vitamin K (IV route preferred in emergencies) for sustained effect
• Monitor INR at 30 minutes, 4-6 hours, and 24 hours after administration
• Dosing of PCC is based on INR and body weight (INR 2-<4: 25 U/kg; INR 4-6: 35 U/kg; INR >6: 50 U/kg) 1

Remember that while vitamin K begins working quickly when given intravenously, the full effect on coagulation takes several hours as it must stimulate new synthesis of clotting factors in the liver.