Phytonadione (Vitamin K1)

Pronunciation: pronunciation varies by local usage.

Generic name: phytonadione
Drug class: Vitamin K supplement; coagulation factor support agent
Form: Injectable emulsion in single-dose ampules (1 mg/0.5 mL neonatal concentration and 10 mg/mL adult concentration); oral tablets (strength not specified in this source)
Route: Subcutaneous, intramuscular, intravenous injection; oral tablet
Legal status: Prescription-only medicine

Availability and supply rules vary by country

Trade names by country: United States

What phytonadione is and how it works

Phytonadione (vitamin K1) has the same type and degree of activity as naturally occurring vitamin K, which is necessary for the liver to produce active clotting factors II (prothrombin), VII, IX, and X. It is used to treat or prevent bleeding related to vitamin K deficiency or to reverse the effects of certain anticoagulants. (1)

Phytonadione is a prescription medicine, available as an injection and as an oral tablet form; oral tablet dosing details were not captured in this source. The subcutaneous route of injection is preferred because of the risk of severe hypersensitivity reactions with intravenous or intramuscular injection. For anticoagulant reversal or deficiency, the dose and route are determined by the treating clinician based on the clinical situation and patient factors.

Mechanism of action: how phytonadione works

Phytonadione is chemically 2-methyl-3-phytyl-1,4-naphthoquinone; it has the same type and degree of activity as naturally occurring vitamin K, which is necessary for the hepatic synthesis of active clotting factors II (prothrombin), VII (proconvertin), IX (plasma thromboplastin component), and X (Stuart factor). (1)

What phytonadione is used for

Anticoagulant-induced hypoprothrombinemia

Used to treat bleeding or excessive anticoagulation caused by coumarin or indanedione-derivative anticoagulants. Dosing is adjusted based on the degree of anticoagulation and prothrombin time/INR response. (1)

Hypoprothrombinemia due to antibacterial therapy

Used when certain antibiotics disrupt vitamin K production or absorption, leading to a deficiency of clotting factors. (1)

Hypoprothrombinemia secondary to factors limiting absorption or synthesis

Includes conditions such as obstructive jaundice, biliary fistula, celiac disease, cystic fibrosis, and other intestinal disorders that impair vitamin K uptake. (1)

Other drug-induced hypoprothrombinemia

Caused by salicylates or other drugs that interfere with vitamin K metabolism. (1)

Neonatal prophylaxis and treatment of vitamin K-deficiency bleeding

Phytonadione is given to newborns to prevent or treat bleeding caused by physiological vitamin K deficiency. A single dose is administered shortly after birth. (1)

Before taking phytonadione

Do not take / not appropriate for

Tell the treating clinician if you have a known hypersensitivity to phytonadione or any component of the product — the clinician will determine whether this product, or a preservative-free formulation, is appropriate. (injectable product reviewed in this source; other phytonadione products were not reviewed) (1)
The subcutaneous route is preferred by the treating team; intravenous and intramuscular use should be avoided when possible due to the risk of fatal hypersensitivity reactions, including anaphylaxis, even with diluted doses and first-time use. (all indications) (1)

Tell your clinician about

Any previous allergic reactions to vitamin K or preservatives such as benzyl alcohol.
If you are pregnant, planning to become pregnant, or breastfeeding—a preservative-free formulation may be needed.
Liver disease, clotting disorders, or conditions affecting vitamin K absorption (e.g., celiac disease, cystic fibrosis).
Current use of anticoagulants such as warfarin or other blood thinners.
If the patient is a neonate or premature infant, especially regarding risks of benzyl alcohol and aluminum accumulation.

(1)

How to take phytonadione

Phytonadione injection is given by the treating clinical team; home self-injection approval status is unresolved from the reviewed source. The dose and route depend on the indication, severity of hypoprothrombinemia, and patient factors.
For anticoagulant-induced hypoprothrombinemia, the prothrombin time/INR should be rechecked 6–8 hours after administration; the treating clinician determines whether a further dose is needed if the response is inadequate.
When the intravenous route is unavoidable, the injection must be given very slowly, not exceeding 1 mg per minute.
The oral tablet should be taken exactly as prescribed; specific oral dosing was not captured in this source and must be verified from the tablet product label.

(1)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)

Missed dose

Missed-dose guidance is

Overdose

Specific overdose/medication-error management guidance is unresolved from the reviewed source.

Side effects

Adverse reactions can occur, particularly with intravenous or intramuscular administration. The most serious risk is fatal anaphylaxis. The subcutaneous route is preferred unless other routes are unavoidable.

Cyanosis, diaphoresis (sweating), dizziness, dysgeusia (taste disturbance), dyspnea, flushing, hypotension, tachycardia

What to notice: These are among the most frequently reported adverse reactions in the reviewed label; specific timing relative to the injection is unresolved from the reviewed source.

What to do: Inform the administering clinician immediately. (1)

Skin reactions

What to notice: Eczematous, pruritic plaques, or scleroderma-like lesions may appear, sometimes with a delayed onset (1 day to 1 year after injection).

What to do: Report any new or worsening skin changes to a clinician. (1)

Severe hypersensitivity or anaphylaxis

What to notice: Difficulty breathing, swelling of the face or throat, rapid heartbeat, severe dizziness, or collapse.

What to do: This is a medical emergency. Emergency treatment should be initiated immediately. (1)

Cardiorespiratory arrest

What to notice: Sudden loss of consciousness and absence of breathing or pulse.

What to do: Requires immediate emergency resuscitation. (1)

Serious warnings

Fatal hypersensitivity reactions (including anaphylaxis) — emergency

Symptoms: Fatal hypersensitivity reactions, including anaphylaxis, have occurred during and immediately after IV and IM injection, even with a diluted product and on a first dose. Symptoms include severe respiratory distress, hypotension, shock, and cardiorespiratory arrest.

Action: The treating clinical team selects the subcutaneous route unless other routes are unavoidable, given the reported risk of fatal hypersensitivity reactions with IV/IM use. Seek immediate emergency medical intervention if symptoms develop. (1)

Benzyl alcohol toxicity in neonates and infants — warning

Symptoms: Exposure to benzyl alcohol, a preservative in this product, can cause serious and fatal adverse reactions including 'gasping syndrome' in neonates and low-birth-weight infants.

Action: The treating clinical team selects a preservative-free formulation for pediatric patients when available, and determines any monitoring needed if a preservative-containing product is used. (1)

Aluminum accumulation in premature neonates — warning

Symptoms: Premature neonates are at particular risk from aluminum exposure; this product contains no more than 110 mcg/L of aluminum. The specific reason premature neonates are at higher risk is unresolved from the reviewed source.

Action: The treating clinical team will determine appropriate use and precautions for premature neonates. (1)

Interactions

Medicine or test	Effect	Action
Coumarin and indanedione-derivative anticoagulants (e.g., warfarin)	Phytonadione may induce temporary resistance to warfarin and other coumarin/indanedione anticoagulants.	The prescribing clinician manages anticoagulant therapy and any related PT/INR monitoring or dose decisions. (1)
Heparin	Phytonadione does not affect the anticoagulant action of heparin.	Heparin management remains a decision for the prescribing clinician; phytonadione does not affect heparin's anticoagulant action. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Vitamin K deficiency during pregnancy increases maternal bleeding risk and may rarely cause fetal intracranial hemorrhage. The label recommends a preservative-free formulation of this injectable product when available; the prescribing clinician determines the formulation and whether and how treatment continues. (1)

Breastfeeding

Phytonadione passes into breast milk. The label recommends a preservative-free formulation of this injectable product when available; the treating clinician selects the formulation. Discuss the risks and benefits with a clinician. (1)

Neonates and infants

The injectable product contains benzyl alcohol, which can cause fatal gasping syndrome in neonates and low-birth-weight infants. The label recommends preservative-free formulations when possible; the treating clinical team selects the formulation. Dosing for neonatal prophylaxis is 0.5–1 mg as a single dose given within one hour of birth; for treatment, 1 mg subcutaneously or intramuscularly. (1)

Monitoring

Before starting

Confirm the indication and assess the severity of hypoprothrombinemia using prothrombin time/INR.
Evaluate for conditions that may impair vitamin K absorption or synthesis.
Check for history of hypersensitivity to phytonadione or product components, including benzyl alcohol.
In neonates, assess gestational age and birth weight to determine risk of benzyl alcohol and aluminum toxicity.

During treatment

For anticoagulant-induced hypoprothrombinemia, recheck prothrombin time/INR at 6–8 hours after administration; the treating clinician determines whether to repeat dosing if the response is inadequate.
Monitor for signs of hypersensitivity, especially during IV or IM injection; ensure emergency resuscitation equipment is available.
Observe neonates for signs of gasping syndrome if a benzyl alcohol-containing product is used.
Assess for cutaneous reactions, which may occur days to months after exposure.

(1)

Storage

Storage conditions were not specified in this source; refer to the product label.

Professional information

This summary is based on a single US label accessed in August 2026. Always consult the current local prescribing information for the specific product and indication.

United States

Indication: Anticoagulant-induced hypoprothrombinemia (adult)

Dose summary: 2.5–10 mg, up to 25–50 mg in severe cases, as a single dose by any of the labeled routes. Recheck PT/INR at 6–8 hours; repeat if needed.

Renal context: No specific renal impairment dose adjustment was captured in this source. (1)

United States

Indication: Non-anticoagulant-induced hypoprothrombinemia (adult)

Dose summary: 2.5–25 mg, up to 50 mg in severe cases, as a single dose by any of the labeled routes.

Renal context: No specific renal impairment dose adjustment was captured in this source. (1)

United States

Indication: Neonatal prophylaxis of vitamin K-deficiency bleeding

Dose summary: 0.5–1 mg as a single dose given within one hour of birth. The specific route for the prophylaxis dose was not established in the reviewed source (route is specified only for the neonatal treatment dose, below).

Renal context: No specific renal impairment dose adjustment was captured in this source. (1)

United States

Indication: Neonatal treatment of vitamin K-deficiency bleeding

Dose summary: 1 mg given subcutaneously or intramuscularly as a single dose.

Renal context: No specific renal impairment dose adjustment was captured in this source. (1)

Mechanism of action

Hepatic guidance

Hepatic-impairment-specific dose adjustments are unresolved from the reviewed source.

Overdose note

Specific overdose/medication-error management guidance is unresolved from the reviewed source. (1)

Frequently asked questions

Why is the subcutaneous route preferred for phytonadione injection?

Fatal hypersensitivity reactions, including anaphylaxis, have occurred during and immediately after intravenous and intramuscular injection, even with a diluted product and on a first dose. Because of this, the subcutaneous route is preferred unless other routes are unavoidable. (1)

Can phytonadione be given orally?

An oral tablet form of phytonadione exists, but this content model's reviewed and registered source is the injectable-product label only. Oral tablet indication, dosing, and product-specific details were not captured from a separately verified source in this pass and must be confirmed from the tablet product's own label. (1)

What is the risk of benzyl alcohol in this product?

The injectable form contains benzyl alcohol as a preservative. In neonates and low-birth-weight infants, benzyl alcohol can cause serious and fatal adverse reactions including 'gasping syndrome'. The label recommends a preservative-free formulation for these patients when available; the treating clinical team selects the formulation. (1)

What is the mechanism of action of phytonadione?

What is the generic name of Phytonadione (Vitamin K1)?

The generic name is phytonadione. (1)

What class of drug is phytonadione?

Phytonadione (Vitamin K1) is classed as: Vitamin K supplement; coagulation factor support agent. (1)

References

Vitamin K1 (phytonadione injection, emulsion)U.S. FDA DailyMed · United States · accessed 2026-08-05 · source 1
Phytonadione — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 2
PHYTONADIONE PHYTONADIONE — FDA approval record (Drugs@FDA ANDA207719)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 3
phytonadione — RxNorm normalized drug concept (RXCUI 8308)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 4

Brand names by country

Single-ingredient phytonadione names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

VITAMIN K1 PHYTONADIONE2 mg/mL, 10 mg/mL · hf acquisition co llc, dba healthfirst
Vitamin K12 mg/mL, 10 mg/mL · hospira, inc.

View brands in additional countries.