phytomenadione: clinical use

Prescribing considerations

• Confirm the indication, anticoagulant involved and whether anticoagulation must continue.
• Severe bleeding requires immediate haemostatic management because phytomenadione does not act immediately.
• Seek haematology advice when considering anticoagulant reversal in infants or children.
• Oral absorption may be unreliable in infants with cholestatic disease.
• Use the route and formulation licensed or clinically appropriate for the indication.

Contraindications and cautions

• Hypersensitivity to phytomenadione or any formulation component.
• Do not give the adult anticoagulant-reversal formulation intramuscularly because of haematoma risk and prolonged release.
• Use particular caution in severe hepatic impairment and premature infants receiving parenteral treatment.

Monitoring

• Clinical bleeding and haemodynamic status.
• INR or other appropriate coagulation tests following anticoagulant reversal.
• Injection or infusion sites for local reactions.
• Liver-related risk factors and bilirubin where clinically relevant in vulnerable neonates.

Clinical pharmacology

Fat-soluble synthetic vitamin K1 supports hepatic gamma-carboxylation and functional activation of vitamin K-dependent coagulation factors and proteins C and S. It antagonises coumarin anticoagulation but does not directly replace clotting factors.

Formulation and product differences

• The adult mixed-micelle ampoule is licensed for intravenous anticoagulant reversal.
• The paediatric mixed-micelle ampoule can be given orally, intramuscularly or intravenously according to the indication.
• The neonatal soft capsule contains liquid intended to be squeezed into the mouth, not swallowed intact.
• Product excipients and handling requirements differ; paediatric ampoule solution must not be diluted before injection.

Capsule

Route: Oral

Strengths: 1 mg

Injection

Route: Parenteral

Strengths: 2 mg/0.2 mL, 10 mg/1 mL, 10 mg/mL