Vitamin K Dosing for Coagulopathy in Acute Hepatitis for a 35 kg Adolescent
For an adolescent weighing 35 kg with coagulopathy due to acute hepatitis, the recommended dose of vitamin K is 5-10 mg intravenously. 1
Dosing Considerations
- For acute coagulopathy management in hepatic disease, vitamin K1 (phytomenadione) should be administered at a dose of 5-10 mg 1
- The route of administration should be intravenous for rapid effect in acute coagulopathy 1
- Lower doses may not fully correct the INR, while doses exceeding 10 mg could potentially create a prothrombotic state 1
Efficacy Considerations
- Vitamin K administration in hepatic coagulopathy shows variable efficacy, with studies demonstrating a median INR reduction of 0.63 after the first dose 2
- Subsequent doses of vitamin K often show diminishing returns in patients with liver disease 2
- The effect of vitamin K is most pronounced when the coagulopathy is due to vitamin K deficiency rather than reduced hepatic synthesis capacity 3, 4
Administration Protocol
- Administer vitamin K intravenously at a slow rate to minimize risk of anaphylactic reaction 1
- Monitor INR regularly after administration to assess response 1
- If using vitamin K with prothrombin complex concentrate (PCC), administer simultaneously to achieve both immediate and sustained correction 1
Safety Considerations
- Be aware that IV vitamin K carries a rare but serious risk of anaphylactic reaction (3 per 100,000 doses) via a non-IgE mechanism 1
- The reaction is possibly due to the solubilizer in the vitamin K solution 1
- Monitor for signs of hypersensitivity during and after administration 1
Additional Management Considerations
- Consider checking fibrinogen levels and maintaining them above 120 mg/dL if there is evidence of ongoing bleeding 1
- In cases of severe coagulopathy with active bleeding, consider additional hemostatic support with prothrombin complex concentrates (PCCs) at 25-50 U/kg 1, 5
- Assess for and treat any underlying infection, as this may exacerbate coagulopathy 1
Monitoring
- Check INR before administration and 6-12 hours after to assess response 1
- Monitor for clinical signs of bleeding 1
- If coagulopathy persists despite vitamin K administration, consider alternative or additional interventions 3, 2
Limitations and Caveats
- Vitamin K therapy may not significantly improve coagulation parameters in patients with severe liver disease due to reduced hepatic synthetic capacity 3
- The efficacy of vitamin K is limited in advanced liver disease where the primary issue is decreased synthesis rather than vitamin K deficiency 3, 4
- Consider specialist consultation if coagulopathy persists despite appropriate vitamin K administration 1