phytonadione
Brand names: Vitamin K1, Mephyton
Phytonadione is a vitamin K supplement. It helps your blood clot properly.
Drug Pricing (NADAC)
Generic Price
$12.59/unit
Generic Available
Yes (15 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine treats bleeding problems caused by low vitamin K levels.
Common side effects
No common side effects listed.
Key warnings
This medicine can cause severe reactions, including death, if given intravenously (into a vein) or intramuscularly (into a muscle).
How It Works
Phytonadione provides vitamin K1, which is needed to make certain clotting factors in your blood. These clotting factors help stop bleeding. By increasing these factors, phytonadione helps your blood clot normally.
How to Take It
Phytonadione is usually given as an injection by a healthcare provider. It can be injected under the skin, into a muscle, or into a vein. The dose depends on your condition and how you respond to the medicine. If injected into a vein, it should be given very slowly.
Pregnancy & Breastfeeding
It is not known if phytonadione can harm an unborn baby. Talk to your doctor if you are pregnant or breastfeeding.
Missed Dose
Since phytonadione is usually given by a healthcare provider, you are not likely to miss a dose. If you are giving yourself the injections, call your doctor if you miss a dose.
Storage
Store at room temperature (68 to 77°F) and protect from light. Keep the ampules in the carton until you are ready to use them.
Side Effects (from patient reports)
Based on 5,026 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 8,078 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 1999–2025.
Total Reports
8,078
Death-Related Reports
1,508
Hospitalization Reports
3,758
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | OFF LABEL USE | 654 |
| 2 | NAUSEA | 630 |
| 3 | VOMITING | 533 |
| 4 | FATIGUE | 523 |
| 5 | DYSPNOEA | 486 |
| 6 | DRUG INEFFECTIVE | 485 |
| 7 | SEPSIS | 446 |
| 8 | DIARRHOEA | 436 |
| 9 | ABDOMINAL PAIN | 428 |
| 10 | CONSTIPATION | 405 |
| 11 | HEADACHE | 372 |
| 12 | ABDOMINAL DISTENSION | 368 |
| 13 | CONDITION AGGRAVATED | 364 |
| 14 | PYREXIA | 346 |
| 15 | ANAEMIA | 344 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
This medicine can cause severe reactions, including death, if given intravenously (into a vein) or intramuscularly (into a muscle). These reactions can resemble an allergic reaction, with shock and cardiac or respiratory arrest. Intravenous and intramuscular routes should only be used if subcutaneous injection is not possible.
Known Drug Interactions
If relatively large doses have been employed, it may be necessary when reinstituting anticoagulant therapy to use somewhat larger doses of the prothrombin-depressing anticoagulant, or to use one which acts on a different principle, such as heparin sodium.
Mechanism: Vitamin K helps blood clot, but heparin works to thin the blood using a different process that Vitamin K does not block.
What to do: Your doctor may use heparin if you need to thin your blood after taking Vitamin K.
Common Questions
What is phytonadione used for?
How is phytonadione given?
What should I do if I experience side effects?
Can I take phytonadione if I am pregnant?
How quickly does phytonadione work?
Will I need blood tests while taking this medicine?
Can phytonadione interact with other medicines?
What if the injection site is painful?
Is phytonadione the same as vitamin K?
What should I avoid while taking phytonadione?
Does phytonadione interact with other medications?
What drug class is phytonadione?
Is phytonadione safe during pregnancy?
Related Medications in Vitamin K Supplement
Other drugs grouped near phytonadione — same-class peers and common alternatives.
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calcitriol
Rocaltrol
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calcium carbonate
Tums, Caltrate
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cholecalciferol
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PNV-DHA is a multivitamin with minerals and essential fatty acids.
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Related Health & Safety Data
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What the FDA Data Shows for phytonadione
The FDA label for phytonadione (sold under brand names such as Vitamin K1, Mephyton) classifies it as a prescription-only medication in the Vitamin K Supplement class. This medicine treats bleeding problems caused by low vitamin K levels. Labeling covers dosing, contraindications, and monitoring requirements derived from clinical trials.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 5,026 voluntary reports. The database also lists 1 documented drug interaction derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS shows a generic unit cost of $12.59.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: May 30, 2019
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages