Comprehensive medication guide to Mephyton including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$15 copay for generic phytonadione on most commercial insurance plans; typically Tier 1–2; Medicare Part D generally covers it as a generic with the $2,100 annual out-of-pocket cap in 2026.
Estimated Cash Pricing
$67–$80 retail for generic phytonadione 5 mg (30 tablets); as low as $21–$27 with GoodRx or SingleCare coupons for a 30-day supply.
Medfinder Findability Score
55/100
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Mephyton is the brand name for phytonadione—a synthetic, prescription-strength form of vitamin K1. It is used to treat vitamin K deficiency and conditions that prevent normal blood clotting. The Mephyton brand has been discontinued, but generic phytonadione 5 mg oral tablets remain available from multiple manufacturers.
Phytonadione is FDA-approved to treat anticoagulant-induced hypoprothrombinemia (including warfarin overdose), hypoprothrombinemia from antibiotics or malabsorption conditions (obstructive jaundice, celiac disease, Crohn's disease), and for prophylaxis and treatment of vitamin K deficiency bleeding in newborns. It is classified as an anticoagulant reversal agent and vitamin K supplement.
Phytonadione is available as 5 mg oral tablets and in injectable forms (1 mg/0.5 mL emulsion and 10 mg/mL solution) for clinical use. The tablets are yellow, round, and scored. The drug requires a valid prescription and is not available over the counter.
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Phytonadione works as a cofactor for a liver enzyme called vitamin K-dependent carboxylase. This enzyme activates four critical blood clotting factors—factors II (prothrombin), VII, IX, and X—by adding a carboxyl group to glutamic acid residues on these proteins, allowing them to bind calcium and participate in the coagulation cascade. Without vitamin K, these factors exist in an inactive form and cannot help blood clot properly.
Warfarin works by blocking vitamin K epoxide reductase (VKOR), the enzyme that recycles vitamin K in the liver. Phytonadione reverses warfarin by providing a large supply of fresh vitamin K that activates a backup (NADPH-dependent) enzyme pathway, allowing the liver to produce functional clotting factors despite warfarin's presence.
Oral phytonadione tablets begin affecting prothrombin time within 6–10 hours; injectable phytonadione shows measurable improvement in 1–2 hours. Phytonadione is a fat-soluble vitamin that requires bile salts for absorption. It is concentrated in the liver, metabolized, and excreted in bile and urine.
5 mg — oral tablet
Standard oral tablet; generic phytonadione from multiple manufacturers; take as directed by prescriber
1 mg/0.5 mL — injectable emulsion
Preservative-free injectable; administered IM or SQ; used in clinical settings including neonatal care
10 mg/mL — injectable solution
Higher-concentration injectable for IV or IM use; administered in monitored clinical settings only
Generic phytonadione 5 mg tablets are available from multiple manufacturers and are not listed in an active FDA shortage as of 2026. However, patients frequently report difficulty finding them because the Mephyton brand is discontinued, causing confusion in pharmacy search systems, and because the medication is relatively low-demand and not routinely stocked at every pharmacy.
The key to finding phytonadione is asking by the generic name—"phytonadione 5 mg tablets"—rather than "Mephyton." Independent pharmacies and hospital-affiliated outpatient pharmacies are often better stocked than major chains for this medication. If a pharmacy doesn't have it today, they can typically order it for next-day availability.
To save time tracking it down, use medfinder—enter your medication, dosage, and location, and medfinder will call pharmacies near you to check which ones have phytonadione in stock today. Results are texted directly to you.
Since phytonadione is not a controlled substance, any licensed prescriber in the United States can prescribe it without DEA registration for the specific drug or special prescribing authority. This includes a broad range of healthcare providers across specialties.
Primary care physicians (PCPs) and internists
Cardiologists (patients on warfarin for AFib, heart valve disease, VTE)
Hematologists (bleeding disorders, coagulopathies)
Gastroenterologists and hepatologists (malabsorption, liver disease)
Nurse practitioners (NPs) and physician assistants (PAs)
Hospitalists and emergency medicine physicians
Telehealth availability: Because phytonadione is not a controlled substance, it can be prescribed by any telehealth provider without the additional restrictions that apply to scheduled medications. Patients seeking a prescription online should have their recent lab work (INR, prothrombin time) available for the visit.
No. Phytonadione is not a controlled substance and has no DEA schedule. It is a prescription-only medication, but any licensed physician, nurse practitioner, or physician assistant can prescribe it without special DEA registration or prescribing authority.
Because phytonadione is not a controlled substance, it can be prescribed via telehealth without the additional regulatory requirements that apply to Schedule II-V medications. Prescriptions can be sent electronically and do not require special prescription paper or in-person visits.
Oral phytonadione tablets are generally very well tolerated with few side effects. Common (though still rare) side effects include:
Taste changes (occasionally reported)
Mild nausea or stomach upset
Skin rash or itching (rare hypersensitivity)
Serious side effects (seek emergency care):
Severe allergic reaction (anaphylaxis): hives, swelling of face/lips/tongue/throat, difficulty breathing — particularly risk with injectable form
Bluish discoloration of skin, nails, or lips (cyanosis)
Signs of blood clot (leg pain/swelling, chest pain, shortness of breath) — risk if over-reversing warfarin
Temporary warfarin resistance (with large doses) — INR monitoring required when restarting warfarin
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4-Factor Prothrombin Complex Concentrate (Kcentra)
Preferred for urgent/emergent warfarin reversal with serious bleeding; replaces clotting factors directly; hospital IV medication only
Fresh Frozen Plasma (FFP)
Contains all clotting factors including vitamin K-dependent ones; used when PCCs are unavailable; hospital-based treatment only
OTC Vitamin K supplements
Available without prescription but are much lower-dose (100-200 mcg vs 5 mg); not therapeutically equivalent for coagulation disorders
Andexanet alfa (Andexxa)
Reversal agent for direct Xa inhibitors (rivaroxaban, apixaban); NOT for warfarin reversal; different mechanism and indication from phytonadione
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Warfarin (Jantoven)
majorDirect pharmacological opposition: phytonadione reverses warfarin's anticoagulant effect. Large doses may cause temporary warfarin resistance requiring INR monitoring when restarting warfarin.
Cholestyramine (Questran)
moderateBile acid sequestrant; significantly reduces absorption of fat-soluble phytonadione. Separate administration by at least 2 hours before or 4-6 hours after cholestyramine.
Colestipol (Colestid)
moderateBile acid sequestrant; reduces phytonadione absorption similar to cholestyramine. Separate doses by at least 2-4 hours.
Orlistat (Alli, Xenical)
moderateBlocks fat absorption; reduces absorption of fat-soluble phytonadione. Monitor INR more closely if taking both medications.
Mineral oil (laxative)
moderateCoats intestinal wall and reduces absorption of fat-soluble vitamins including vitamin K. Avoid concurrent use with phytonadione.
Broad-spectrum antibiotics (erythromycin, quinolones)
moderateAlter intestinal flora that produce vitamin K2; may affect overall vitamin K levels. Monitor clotting function during prolonged antibiotic therapy.
Aspirin/NSAIDs (ibuprofen, naproxen)
moderateAdditive anticoagulation risk when combined with phytonadione-warfarin management; increases bleeding risk independently.
St. John's Wort (herbal)
moderateMay affect CYP enzyme metabolism and anticoagulation balance in patients also taking warfarin.
Phytonadione is a clinically essential medication for patients managing warfarin therapy, vitamin K deficiency, or conditions that impair vitamin K absorption. While the Mephyton brand has been discontinued, generic phytonadione remains available from multiple manufacturers and is generally affordable—especially with GoodRx or SingleCare discount coupons that can bring the cost to $21–$27 for a 30-tablet supply.
The main challenge patients face is not drug unavailability, but pharmacy stocking gaps and brand name confusion. Asking specifically for "phytonadione 5 mg tablets" and trying multiple pharmacies—including independent pharmacies—resolves most availability issues. For patients on long-term therapy, switching to mail-order through their insurance PBM eliminates the search problem entirely.
If you're struggling to find phytonadione at your local pharmacy, medfinder can call pharmacies near you to check which ones have it in stock and can fill your prescription today—saving you time and frustration.
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Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
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