Vitamin K1

Treatment of anticoagulant rodenticide toxicity (brodifacoum, warfarin) and vitamin K-responsive coagulopathies. Vitamin K1 (phytonadione). Mechanism: fat-soluble vitamin that serves as cofactor for vitamin K-dependent carboxylase → activates clotting factors II, VII, IX, X, protein C, protein S (glutamate carboxylation → functional coagulation proteins). Antidote for anticoagulant rodenticide (superwarfarin) poisoning — restores carboxylation of vitamin K-dependent clotting factors. Oral or injectable. Key information Phytonadione — antidote for anticoagulant rodenticide toxicity. SC or IM preferred (IV anaphylaxis risk). Duration of treatment: 4–6 weeks for second-generation rodenticides. Oral: administer with fatty meal. Store at room temperature; protect from light.

SQ or IM preferred over IV: inject SQ into loose skin fold or deep IM. IV (rarely): dilute and administer very slowly — anaphylaxis risk. Oral (for extended treatment of superwarfarin toxicity): Administer orally. May be given with food to improve compliance and reduce GI upset. Administer with food to reduce GI adverse effects. (fatty meal improves absorption). Administer every 8–12 hrs for acute emergency; twice daily for maintenance. Store at room temperature; protect from light. If a dose is missed Administer as soon as you remember. If it is almost time for the next scheduled dose, skip the missed dose and resume the normal schedule. Never double up doses to make up for a missed one. Vitamin K1 treatment for anticoagulant rodenticide toxicity requires 4–6 weeks of consistent dosing — do not miss doses.

IM injection: pain, local swelling, hematoma. Rare: anaphylactic reactions (IV route — inject slowly or SQ/IM preferred). High IV dose: facial flushing, urticaria, cardiovascular reactions. Oral: generally well tolerated. Dogs: vomiting (uncommon).

For animals IV: administer SLOWLY — anaphylaxis risk with rapid injection; SQ or oral routes preferred when possible. Oral requires fat absorption — give with fatty meal. Duration of treatment depends on toxin (superwarfarin rodenticides may require 4–6 weeks). Monitor PT/INR to guide duration. For people handling this medication Wear gloves when handling. Wash hands thoroughly with soap and water after handling. Phytonadione — injectable form: administered by veterinary staff. IV injection risk in humans: anaphylaxis possible (give slowly). Generally safe for oral forms. Keep out of reach of children. Pregnant women and women of childbearing age should avoid contact.

Contact your veterinarian. Vitamin K1 overdose is rarely toxic. Administer with a fatty meal for best absorption. Contact your veterinarian or a veterinary emergency clinic immediately if you believe your animal has received an overdose. Bring the medication label and note the approximate amount given.