Indications
Phytomenadione is vitamin K1. It is used:
- To prevent vitamin K deficiency bleeding in newborn babies.
- To reverse the effect of blood thinners such as Warfarin and Acenocoumarol when the blood is too thin or there is bleeding.
- To treat bleeding or a raised bleeding tendency caused by low vitamin K, for example in poor fat absorption, long-term antibiotic use or some liver and bowel diseases.
How It Works
The liver needs vitamin K to make several clotting factors, the proteins that help blood form clots. Phytomenadione replaces missing vitamin K so these factors can be made again, usually within several hours.
Dosage and Administration
Newborns: commonly a single 1 mg injection into the muscle soon after birth, or an oral course, as advised by the doctor or midwife. Reversal of blood thinners and treatment of bleeding: the dose depends on the blood test (INR) and how serious the bleeding is, and is as prescribed. Injections are given by a doctor or nurse; when given into a vein it is injected very slowly. Capsules or oral liquid are taken by mouth only as prescribed.
Interactions
- It reduces the effect of Warfarin and similar blood thinners; after large doses these may be hard to restart for a while.
- It does not reverse Heparin or newer blood thinners such as Rivaroxaban, Apixaban or Dabigatran.
- Long-term antibiotics, Cholestyramine, Orlistat and mineral oil can lower vitamin K levels.
Contraindications
Allergy to phytomenadione or any ingredient of the product.
Side Effects
Usually well tolerated. Possible:
- Pain, swelling or redness at the injection site.
- Flushing, a change in taste, or sweating.
- Rarely, a severe allergic reaction, mainly when injected into a vein.
- In premature babies, high doses may increase jaundice.
Get urgent medical help for difficulty breathing, chest tightness, swelling of the face or throat, fainting or collapse, or if bleeding does not stop.
Pregnancy and Lactation
It may be used in pregnancy when a doctor advises it. Only small amounts pass into breast milk and it is considered safe while breastfeeding.
Precautions and Warnings
- People on long-term blood thinners for artificial heart valves or clots need careful dosing, as too much can raise the clot risk.
- The response may be weaker in severe liver disease.
- Regular INR tests are needed when it is used to reverse blood thinners.
Overdose
Vitamin K1 has low toxicity. Too much in a person on blood thinners can make the blood clot too easily; in newborns it may worsen jaundice. Seek medical advice.
Therapeutic Class
Vitamin K (fat-soluble vitamin); antidote to coumarin blood thinners.
Storage
Store below 30°C, protected from light; do not freeze. Keep in a dry place out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.