|PHYTONADIONE (VITAMIN K1)
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.
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.
Pregnancy (category C); lactation. Effect on fertility and teratogenic potential is not known.
Adult: PO/SC/IM 2.510 mg; rarely up to 50 mg/d, may repeat parenteral dose after 68 h if needed or PO dose after 1224 h IV Emergency only: 1015 mg at a rate of 1 mg/min, may be repeated in 4
h if bleeding continues
Hemorrhagic Disease of Newborns
Infant: IM/SC 0.51 mg immediately after delivery, may repeat in 68 h if necessary
Other Prothrombin Deficiencies
Adult: IM/SC 225 mg
Child: IM/SC 510 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.
- Give IM injection in adults and older children in upper outer quadrant of buttocks. For infants and young children, anterolateral
aspect of thigh or deltoid region is preferred.
- Aspirate carefully to avoid intravascular injection.
- Apply gentle pressure to site following injection. Swelling (internal bleeding) and pain sometimes occur with SC or IM administration.
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.
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.
- Protect infusion solution from light by wrapping container with aluminum foil or other opaque material.
- Discard unused solution and contents in open ampul.
Falsely elevated urine steroids (by modifications of Reddy,
Drug: Antagonizes effects of warfarin,
mineral oil decrease absorption of oral phytonadione.
Absorption: Readily absorbed from intestinal lymph only if bile is present. Onset: 612 h PO; 12 h IM/SC; 15 min IV. Peak: Hemorrhage usually controlled within 38 h; normal prothrombin time may be obtained in 1214 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.
Assessment & Drug Effects
- Monitor patient constantly. Severe reactions, including fatalities, have occurred during and immediately after IV injection
(see ADVERSE EFFECTS).
- Lab tests: Baseline and frequent PT/INR.
- Frequency, dose, and therapy duration are guided by PT/INR clinical response.
- Monitor therpeutic effectiveness which is indicated by shortened PT, INR, bleeding, and clotting times, as well as decreased
- Be aware that patients on large doses may develop temporary resistance to coumarin-type anticoagulants. If oral anticoagulant
is reinstituted, larger than former doses may be needed. Some patients may require change to heparin.
Patient & Family Education
- Maintain consistency in diet and avoid significant increases in daily intake of vitamin Krich foods when drug regimen
is stabilized. Know sources rich in vitamin K: Asparagus, broccoli, cabbage, lettuce, turnip greens, pork or beef liver, green
tea, spinach, watercress, and tomatoes.