Last reviewed 2026-04-20 · How we verify

Vitamin K1 (Phytonadione)

Phytonadione (Vitamin K1), marketed by Pfizer Inc., is a well-established treatment for anticoagulant-induced prothrombin deficiency, with a key composition patent expiring in 2028. Its primary strength lies in its essential role as a cofactor for the gamma-carboxylation of vitamin K-dependent clotting factors, making it indispensable for reversing the effects of vitamin K antagonists like warfarin. The primary risk is the increasing competition from newer anticoagulants such as Apixaban and Dabigatran, which offer more predictable pharmacokinetics and reduced need for vitamin K monitoring.

At a glance

Approved indications

• Anticoagulant-induced prothrombin deficiency
• Hemorrhagic disease of the newborn
• Hypoprothrombinemia due to antibacterial therapy
• Hypoprothrombinemia due to absorption or synthesis issues
• Other drug-induced hypoprothrombinemia

Boxed warnings

• BOXED WARNING WARNING — INTRAVENOUS AND INTRAMUSCULAR USE Severe reactions, including fatalities, have occurred during and immediately after INTRAVENOUS injection of phytonadione, even when precautions have been taken to dilute the phytonadione and to avoid rapid infusion. Severe reactions, including fatalities, have also been reported following INTRAMUSCULAR administration. Typically these severe reactions have resembled hypersensitivity or anaphylaxis, including shock and cardiac and/or respiratory arrest. Some patients have exhibited these severe reactions on receiving phytonadione for the first time. Therefore the INTRAVENOUS and INTRAMUSCULAR routes should be restricted to those situations where the subcutaneous route is not feasible and the serious risk involved is considered justified.

Common side effects

• Deaths
• Flushing sensations
• Peculiar sensations of taste
• Dizziness
• Rapid and weak pulse
• Profuse sweating
• Brief hypotension
• Dyspnea
• Cyanosis
• Pain at injection site
• Swelling at injection site
• Tenderness at injection site

Drug interactions

• prothrombin-depressing anticoagulants

Key clinical trials

• A Study of BPM31510 With Vitamin K1 in Subjects With Newly Diagnosed Glioblastoma (GB) (PHASE2)
• The Role of Vitamin K on Knee Osteoarthritis Outcomes (PHASE1, PHASE2)
• Effects of Vitamin K on Lower-extremity Function in Adults With Osteoarthritis: (NA)
• Better Evidence and Translation for Calciphylaxis (PHASE3)
• Bioavailability of Different Vitamin K Vitamers Studied Using 13C-labelled Vitamin K Vitamers (NA)
• Predictive Value of Coronary Heart Disease (CHD) Biomarkers for CHD Death
• Vitamin K and Cognition in Coronary Heart Disease (NutriCog) (NA)
• Efficacy and Safety of Intravenous Vitamin K1 in Management of Acute Variceal Bleeding (PHASE4)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Vitamin K1 CI brief — competitive landscape report
• Vitamin K1 updates RSS · CI watch RSS
• Pfizer Inc. portfolio CI