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Vitamin K1 Side Effects

Generic name: phytonadione

Medically reviewed by Last updated on Aug 5, 2021.

Note: This document contains side effect information about phytonadione. Some of the dosage forms listed on this page may not apply to the brand name Vitamin K1.

For the Consumer

Applies to phytonadione: capsule, tablet

Other dosage forms:

Side effects requiring immediate medical attention

Along with its needed effects, phytonadione (the active ingredient contained in Vitamin K1) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur while taking phytonadione:

Less common

- With menadiol or high doses of phytonadione in newborns
  • Decreased appetite
  • decreased movement or activity
  • difficulty in breathing
  • enlarged liver
  • general body swelling
  • irritability
  • muscle stiffness
  • paleness
  • yellow eyes or skin


- With injection only
  • Difficulty in swallowing
  • fast or irregular breathing
  • lightheadedness or fainting
  • shortness of breath
  • skin rash, hives and/or itching
  • swelling of eyelids, face, or lips
  • tightness in chest
  • troubled breathing and/or wheezing


Side effects not requiring immediate medical attention

Some side effects of phytonadione may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

  • Flushing of face
  • redness, pain, or swelling at place of injection
  • skin lesions at place of injection (rare)
  • unusual taste

For Healthcare Professionals

Applies to phytonadione: compounding powder, injectable solution, oral tablet


Rare (less than 0.1%): Injection site reactions (inflammation, atrophy, necrosis)

Very rare (less than 0.01%): Venous irritation or phlebitis (IV route)

Frequency not reported: Pain, swelling, and tenderness at the injection site[Ref]


Rare (less than 0.1%): Rapid and weak pulse, hypotension, cyanosis

Very rare (less than 0.01%): Facial flushing

Postmarketing reports: Tachycardia, flushing[Ref]


Fatalities and other severe reactions have occurred during or immediately after the parenteral administration of phytonadione (the active ingredient contained in Vitamin K1) The majority of these reactions have occurred with intravenous administration. These reactions resemble hypersensitivity or anaphylaxis and include shock and cardiac or respiratory arrest. Feelings of uneasiness, flushing, diaphoresis, chest pain, tachycardia, cyanosis, weakness, and dyspnea may precede the cardiopulmonary event. These severe reactions are more likely with, but are not limited to, rapid infusions of undiluted drug.[Ref]

Very rare (less than 0.01%): Anaphylactoid reactions (IV route)

Frequency not reported: Allergic sensitivity, anaphylaxis

Postmarketing reports: Fatal hypersensitivity reaction[Ref]


Gastrointestinal side effects have rarely included 'peculiar' sensations of taste.


Rare (less than 0.1%): Dyspnea[Ref]


Frequency not reported: Death (IV and IM routes)[Ref]


Uncommon (0.1% to 1%): Erythematous, indurated, pruritic plaques

Rare (less than 0.1%): Profuse sweating, scleroderma-like lesions,

Very rare (less than 0.01%): Sweating

Frequency not reported: Erythema perstans-like lesions[Ref]

Nervous system

Rare (less than 0.1%): Dizziness

Very rare (less than 0.01%): Unusual taste

Postmarketing reports: Dysgeusia[Ref]


Hyperbilirubinemia occurred primarily with doses above those recommended.[Ref]

Rare (less than 0.1%): Hyperbilirubinemia

Frequency not reported: Jaundice in newborns[Ref]


Frequency not reported: Hemolysis in newborns[Ref]


The most common adverse events were dermatologic and injection site reactions.[Ref]


1. Cerner Multum, Inc. "Australian Product Information." O 0

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. "Product Information. Vitamin K Injection (phytonadione)." Abbott Pharmaceutical, Abbott Park, IL.

4. "Product Information. Mephyton (phytonadione)." Merck & Co, Inc, West Point, PA.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.