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Vitamin K (Phytonadione): uses, side effects & brands
Vitamin K supports clotting and reverses over-thinning from warfarin. It belongs to the Antidote & chelation group. These reverse poisoning, correct overloads or restore clotting.
Drug type — dosing is set by your doctor
| Measure | Range |
|---|---|
| Drug class | Antidote & chelation |
| Type | Prescription |
| Dose | Individual — ask your doctor or pharmacist |
What it is used for
- Reversing over-thinning from warfarin
- Preventing bleeding in newborn babies
- Bleeding from vitamin K deficiency (e.g. liver or absorption problems)
Common brand names
- India: Kapvit, Vitamin K1
- Worldwide: Mephyton, Konakion
Common side effects
- Pain or swelling at the injection site
- Flushing or altered taste (injection)
- Few side effects when taken by mouth
Before taking it — precautions
- Tell your doctor if you take warfarin; it can make warfarin less effective for a while
- Injection into a vein is given slowly in hospital
- Does not reverse newer blood thinners like apixaban or rivaroxaban
When to see a doctor urgently
- Facial swelling, wheeze or collapse after injection (urgent)
- Any ongoing bleeding (urgent)
- Signs of a clot such as leg swelling or chest pain
Not a prescription — no dose shown. The right dose of vitamin k depends on age, weight, kidney/liver function and the condition, so MedDroid does not show a dose here. Always get your dose from a doctor or pharmacist and the leaflet inside the pack. General educational information only.
Frequently asked questions
Why do newborns get a vitamin K injection?
Babies are born with low vitamin K, and a dose at birth prevents rare but serious bleeding.
Should I avoid green vegetables on warfarin?
No need to avoid them, but keep your intake steady, because vitamin K in food changes how warfarin works.
Does it work immediately?
It takes some hours to work. In serious bleeding doctors may also give clotting factor products.
Explore more
Sources & further reading
- World Health Organization (WHO)
- MedlinePlus — U.S. National Library of Medicine
- Ministry of Health & Family Welfare, India
- Indian Council of Medical Research (ICMR)
Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.