Vitamin K
Brand: (Mephyton and AquaMephyton discontinued; generic only)
Boxed warning
Phytonadione injection only: fatal hypersensitivity reactions including anaphylaxis with IV and IM use, so IV is reserved for when other routes are not feasible; oral vitamin K carries no boxed warning.
- Caution
- Effect takes hours: active bleeding on warfarin is treated with clotting factors or plasma as well.
- Storage
- Protect from light; keep ampules in the carton until use.
Common side effects
- Flushing
- Injection-site pain
- Rarely, severe reaction with IV use
- Altered taste
Key interactions
- Directly opposes warfarin: dietary intake should stay consistent
Counseling points
- Given for a high INR or active bleeding on warfarin
- Effect takes hours. Blood products are used when bleeding is active
- Keep green leafy vegetable intake steady rather than avoiding it
- Also treats bleeding from vitamin K deficiency
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