AquaMEPHYTON, Konakion, Mephyton, Phylloquinone
Classifications: hormones and synthetic substitutes; vitamin; antidote
Pregnancy Category: C


5 mg tablets; 2 mg/mL, 10 mg/mL injection


Fat-soluble naphthoquinone derivative chemically identical to and with similar activity as naturally occurring vitamin K. Vitamin K is essential for hepatic biosynthesis of blood clotting Factors II, VII, IX, and X.

Therapeutic Effects

Promotes liver synthesis of clotting factors by unknown mechanism. Does not reverse anticoagulant action of heparin. Reportedly demonstrates wide margin of safety when used in newborns.


Drug of choice as antidote for overdosage of coumarin and indandione oral anticoagulants. Also reverses hypoprothrombinemia secondary to administration of oral antibiotics, quinidine, quinine, salicylates, sulfonamides, excessive vitamin A, and secondary to inadequate absorption and synthesis of vitamin K (as in obstructive jaundice, biliary fistula, ulcerative colitis, intestinal resection, prolonged hyperalimentation). Also prophylaxis of and therapy for neonatal hemorrhagic disease.


Hypersensitivity to AquaMEPHYTON; severe liver disease.

Cautious Use

Pregnancy (category C); lactation. Effect on fertility and teratogenic potential is not known.

Route & Dosage

Anticoagulant Overdose
Adult: PO/SC/IM 2.5–10 mg; rarely up to 50 mg/d, may repeat parenteral dose after 6–8 h if needed or PO dose after 12–24 h IV Emergency only: 10–15 mg at a rate of 1 mg/min, may be repeated in 4 h if bleeding continues

Hemorrhagic Disease of Newborns
Infant: IM/SC 0.5–1 mg immediately after delivery, may repeat in 6–8 h if necessary

Other Prothrombin Deficiencies
Adult: IM/SC 2–25 mg
Child: IM/SC 5–10 mg
Infant: IM/SC 1 mg



Note: Konakion, which contains a phenol preservative, is intended ONLY for IM use. AquaMEPHYTON may be given SC, IM, or IV as prescribed.

  • Note: Reserve IV route only for emergencies.

PREPARE: Direct: Dilute a single dose in 10 mL D5W, NS, or D5/NS.  

ADMINISTER: Direct: Give solution immediately after dilution at a rate not to exceed 1 mg/min.  

INCOMPATIBILITIES Solution/additive: Ranitidine Y-site: Dobutamine.

  • Protect infusion solution from light by wrapping container with aluminum foil or other opaque material.
  • Discard unused solution and contents in open ampul.

Adverse Effects (1%)

Body as a Whole: Hypersensitivity or anaphylaxis-like reaction: facial flushing, cramp-like pains, convulsive movements, chills, fever, diaphoresis, weakness, dizziness, shock, cardiac arrest. CNS: Headache (after oral dose), brain damage, death. GI: Gastric upset. Hematologic: Paradoxic hypoprothrombinemia (patients with severe liver disease), severe hemolytic anemia. Metabolic: Hyperbilirubinemia, kernicterus. Respiratory: Bronchospasm, dyspnea, sensation of chest constriction, respiratory arrest. Skin: Pain at injection site, hematoma, and nodule formation, erythematous skin eruptions (with repeated injections). Special Senses: Peculiar taste sensation.

Diagnostic Test Interference

Falsely elevated urine steroids (by modifications of Reddy, Jenkins, Thorn procedure).


Drug: Antagonizes effects of warfarin, cholestyramine, colestipol, mineral oil decrease absorption of oral phytonadione.


Absorption: Readily absorbed from intestinal lymph only if bile is present. Onset: 6–12 h PO; 1–2 h IM/SC; 15 min IV. Peak: Hemorrhage usually controlled within 3–8 h; normal prothrombin time may be obtained in 12–14 h after administration. Distribution: Concentrates briefly in liver after absorption; crosses placenta; distributed into breast milk. Metabolism: Rapidly metabolized in liver. Elimination: Excreted in urine and bile.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug