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Generic Name: phytonadione (fye toe na DYE own)
Brand Name: Mephyton, Vitamin K1, Aquamephyton, Konakion

What is phytonadione?

Phytonadione is a man-made form of vitamin K, which occurs naturally in the body.

Phytonadione is used to treat vitamin K deficiency and to treat certain bleeding or blood clotting problems.

Phytonadione may also be used for purposes not listed in this medication guide.

Important Information

Before using phytonadione tell your doctor about all your medical conditions or allergies, all medicines you use, and if you are pregnant or breast-feeding.

Never take phytonadione in larger amounts, or for longer than recommended by your doctor.

Before taking this medicine

You should not be treated with phytonadione if you are allergic to it.

Before you receive phytonadione, tell your doctor about all your medical conditions or allergies.

To make sure you can safely take phytonadione, tell your doctor if you have liver disease.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether phytonadione passes into breast milk or if it could affect the nursing baby. Tell your doctor if you are breast-feeding.

How should I use phytonadione?

Follow all directions on your prescription label. Your doctor may occasionally change your dose. Never take this medicine in larger amounts, or for longer than prescribed.

Do not give a injection to a child without medical advice. Injectable phytonadione contains an ingredient that can cause serious side effects or death in very young infants or premature babies. Do not allow an older child to use this medicine without supervision of an adult.

While using phytonadione, you may need frequent blood tests.

If you need surgery or dental work, tell the surgeon or dentist ahead of time that you are using phytonadione.

Store at room temperature away from moisture and heat. Protect from light. Keep the medicine in the original container and tightly closed when not in use.

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose of phytonadione.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking phytonadione?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Phytonadione side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • a light-headed feeling, like you might pass out;

  • blue colored lips;

  • trouble breathing;

  • weak but rapid pulse; or

  • skin redness, itching, or a hard lump where an injection was given.

Common side effects may include:

  • dizziness;

  • flushing (warmth, redness, or tingly feeling);

  • changes in your sense of taste;

  • sweating; or

  • pain or swelling where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

Phytonadione dosing information

Usual Adult Dose for Hypoprothrombinemia -- Anticoagulant Induced:

Initial dose: 2.5 to 10 mg, orally, subcutaneously, or IV
Maximum dose: Up to 25 mg (rarely up to 50 mg)

-Give subcutaneously rather than IV whenever possible.
-If IV administration must be used, inject very slowly, not exceeding 1 mg/minute.

Use: Coumarin or indanedione anticoagulant-induced prothrombin deficiency

Usual Adult Dose for Hypoprothrombinemia -- Not Associated with Anticoagulant Therapy:

Initial dose: 2.5 to 25 mg or more, orally or subcutaneously (SC)
Maximum dose: Rarely up to 50 mg

-Use concurrent bile salts if giving orally if obstructive jaundice or biliary fistula are present, otherwise vitamin K will not be absorbed.

The following coagulation disorders when caused by deficiency or interference with vitamin K activity:
-Hypoprothrombinemia secondary to antibacterials or salicylates;
-Hypoprothrombinemia secondary to obstructive jaundice or biliary fistulas;
-Hypoprothrombinemia secondary to limited absorption or synthesis of vitamin K, e.g., sprue, ulcerative colitis, celiac disease, intestinal resection, cystic fibrosis of the pancreas, and regional enteritis
-Other drug-induced hypoprothrombinemia where it is definitely shown that the result is due to interference with vitamin K metabolism, e.g., salicylates

Usual Pediatric Dose for Hypoprothrombinemia -- Prophylaxis:

0.5 to 1 mg, IM, once, within one hour of birth

Use: Prophylaxis and therapy of hemorrhagic disease of the newborn when caused by deficiency or interference with vitamin K activity

Usual Pediatric Dose for Vitamin K Deficiency:

0.5 to 1 mg, IM, once, within one hour of birth

Use: Prophylaxis and therapy of hemorrhagic disease of the newborn when caused by deficiency or interference with vitamin K activity

Usual Pediatric Dose for Hypoprothrombinemia -- Not Associated with Anticoagulant Therapy:

1 mg, subcutaneously or IM

-Empiric vitamin K should not replace proper lab evaluation of the coagulation mechanism.
-A prompt response (prothrombin time shortened in 2 to 4 hours) is usually diagnostic of hemorrhagic disease of the newborn;
-Failure to respond indicates another diagnosis or coagulation disorder.
-Whole blood or component therapy may be needed for excessive bleeding, however vitamin K should still be given to correct the underlying disorder.

Use: Hemorrhagic disease of the newborn.

What other drugs will affect phytonadione?

Tell your doctor about all your current medicines and any you start or stop using, especially:

  • a blood thinner--warfarin, Coumadin, Jantoven.

This list is not complete. Other drugs may interact with phytonadione, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Where can I get more information?

  • Your pharmacist can provide more information about phytonadione.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 3.01.

Date modified: January 03, 2018
Last reviewed: July 28, 2017