phytonadione
Phytonadione is a vitamin K supplement that helps prevent bleeding in adults with certain blood clotting conditions or those taking medications like warfarin. It comes as a tablet that's taken by mouth, and your prescriber will recommend a dose based on your lab tests. Side effects from the tablet are rare. There's also an injection form commonly given to newborn babies to prevent internal bleeding since they have low vitamin K levels at birth.
What is Phytonadione?
What is Phytonadione used for?
Treatment of blood clotting problems caused by:
Blood thinners like warfarin
Conditions that affect how your body absorbs or makes vitamin K (e.g. jaundice, celiac disease, ulcerative colitis)
Medications that interfere with vitamin K, like aspirin.
How Phytonadione works
Phytonadione is a vitamin K supplement. Vitamin K is an essential vitamin your liver needs to make clotting factors — proteins that help your blood clot and prevent excessive bleeding.
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What are the side effects of Phytonadione?
Common Side Effects
Other Side Effects
- Allergic reactions
- Flushing sensation
- Unusual taste
- Dizziness
- Fast or weak pulse
- Sweating
- Low blood pressure
- Trouble breathing
- Blue skin (cyanosis)
- High bilirubin levels in newborn babies
Source: DailyMed
The following side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
Pros and cons of Phytonadione
Pros
The only oral pill to prevent bleeding caused by warfarin
Sometimes only 1 or 2 doses are needed
Dose can be adjusted based on how you respond
Cons
Takes several hours to start working, so not a good option for emergencies or major bleeding
Usually needs repeat blood tests to check if it's working
Can cause too much clotting if not dosed carefully
Pharmacist tips for Phytonadione
Phytonadione tablets take 6 to 10 hours to work, so it might not be fast enough for serious bleeding. If you have major bleeding, get medical help right away.
Phytonadione breaks down quickly when exposed to light. Always keep the tablets protected from light by storing them in their original, closed vial until you’re ready to take them.
You’ll need blood tests after taking phytonadione because it works differently for everyone. Make sure to get blood tests and follow up with your prescriber.
If you have severe liver or gallbladder problems, you might need to take phytonadione with bile salts to help your body absorb it properly.
Phytonadione can interact with blood thinners, temporarily making them work less well. If this happens, your prescriber might need to change your blood thinner dose or recommend a different one, like heparin.
Phytonadione is a higher strength and prescribed for specific blood clotting problems, compared to OTC vitamin K supplements. Talk to your prescriber before taking any vitamin K supplements to make sure they are safe for you.
Frequently asked questions about Phytonadione
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What are the risks and warnings for Phytonadione?
Phytonadione can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Taking too much phytonadione
If you’re taking phytonadione to treat blood thinning caused by anticoagulant medications like warfarin, you might be at risk of the same clotting problems that led to starting the anticoagulant in the first place, such as atrial fibrillation, pulmonary embolism (PE), or deep vein thrombosis (DVT). Phytonadione isn't a clotting agent, but taking too much can bring back conditions that raise your risk of dangerous blood clots. It’s important to take the lowest dose needed. Your prescriber will check your blood tests regularly to make sure your dose is right for your condition.
Phytonadione dosage forms
Typical dosing for Phytonadione
The typical starting dose is 2.5 mg to 10 mg taken by mouth as a single dose, but it can go up to 25 mg in some cases. In rare situations, 50 mg might be needed. Your prescriber will decide how much and how often you should take phytonadione based on your lab tests and your overall health.
Phytonadione is also available as an injection form, which is usually given in the hospital or clinic.
How much does Phytonadione cost?
What are alternatives to Phytonadione?
Treatment of blood clotting problems caused by:
Blood thinners like warfarin
Conditions that affect how your body absorbs or makes vitamin K (e.g. jaundice, celiac disease, ulcerative colitis)
Medications that interfere with vitamin K, like aspirin.
Treatment of a major bleed in people taking warfarin (Coumadin)
Prevention of bleeding in people taking warfarin (Coumadin) who need an urgent surgery or procedure
Phytonadione images
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References
Best studies we foundAgnitio Inc. (2024). Phytonadione tablet [package insert]. DailyMed.
Glenmark Pharmaceuticals Inc. (2024). Phytonadione injection, emulsion [package insert]. DailyMed.
Lipsky, J. J. (1988). Antibiotic-associated hypoprothrombinaemia. The Journal of Antimicrobial Chemotherapy.
National Institutes of Health. (2021). Vitamin K: Fact sheet for consumers.
Palta, S., et al. (2014). Overview of the coagulation system. Indian Journal of Anaesthesia.
U.S. Department of Health and Human Services and Food and Drug Administration. (2023). Determination that Mephyton (phytonadione) tablets, 5 milligrams, were not withdrawn from sale for reasons of safety or effectiveness. Federal Register.
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