Phytomenadione parenteral
- Drugs List
- Therapeutic Indications
- Dosage
- Administration
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Injection containing 10mg phytomenadione (Vitamin K1) per 1ml in a mixed micelles vehicle of glycocholic acid and lecithin.
Drugs List
Therapeutic Indications
Uses
Antidote to coumarin-type anticoagulant overdosage
Treatment as an antidote to anticoagulant drugs of the coumarin type in the treatment of haemorrhage or threatened haemorrhage, associated with a low blood level of prothrombin or factor VII.
Treatment in children can be considered in disorders that interfere with absorption of vitamin K, poor nutrition and hepatic disease.
Dosage
Patients should stop the anticoagulant coumarin. Dose recommendations are based on warfarin anticoagulant therapy. Other anticoagulants (such as acenocoumarol) have different half lives and phytomenadione dose requirements may differ. Prothrombin complex concentrate (PCC) to be given together, particularly in severe or life-threatening haemorrhage. Fresh frozen plasma (FFP) can be given if PCC is not available.
Adults
Potentially fatal or severe haemorrhages
5mg to 10 mg of phytomenadione by slow intravenous injection.
Maximum dose: 40mg in 24 hours.
Less severe haemorrhage
INR greater than 9: Give 1mg.
INR between 5 and 9: Give 500micrograms to 1mg.
Reversal of anticoagulation prior to surgery
Emergency surgery that can be delayed 6 to 12 hours: Give 5mg intravenously.
Elective surgery (unlicensed): Give 1mg to 5mg phytomenadione using the intravenous solution orally. If INR greater than or equal to 1.5, give dose on the day before surgery.
The following alternative dosing schedules may be suitable:
INR greater than 8 with minor bleeding
Give 1mg to 3mg. Repeat if INR still too high after 24 hours. Restart warfarin when INR less than 5.
INR greater than 8 with no bleeding
Give 1mg to 5mg. Repeat if INR still too high after 24 hours. Restart warfarin when INR less than 5.
INR 5 to 8 with minor bleeding
Give 1mg to 3mg. Restart warfarin when INR less than 5.
Elderly
Dosage should be at the lower end of the ranges recommended as elderly patients tend to be more sensitive to reversal of anticoagulation with phytomenadione.
Children
Children aged 1 to 18 years
Suggested dosages based on clinical experience are as follows:
Major and life threatening bleeding
5mg intravenously.
Children with asymptomatic high INR with or without mild haemorrhage
30micrograms/kg intravenously. Repeat if necessary.
Patients with Hepatic Impairment
Phytomenadione mixed micelles injection contains 54.6mg glycocholic acid per ampoule and this may have a bilirubin displacing effect.
Administration
To be administered by slow intravenous injection or intravenous infusion.
Contraindications
Children under 1 year
Precautions and Warnings
Children aged 1 to 18 years
Elderly
Breastfeeding
Pregnancy
Prosthetic heart valve
Severe hepatic impairment
Fresh frozen plasma should be used in patients with prosthetic heart valves
Patients with prosthetic heart valves: only use if there is major bleeding
Children under 18 treatment should be initiated/supervised by haematologist
Administer IV injection slowly
Use only if the solution is clear
Monitor international normalised ratio (INR)
Severe haemorrhage: consider transfusion of whole blood or clotting factors
May cause anaphylactic / anaphylactoid reactions
Reduce dose in elderly
It should be noted that the earliest effect seen with phytomenadione treatment is at 4-6 hours.
This is not an antidote to heparin.
Large doses of greater than 40 mg should be avoided if it is intended to continue with anticoagulant therapy as there is no experience with doses above 40 mg/day and higher doses may give rise to unexpected adverse events.
Children under 18 years
In patients on warfarin therapy, consider reason for warfarin treatment and whether or not anticoagulant therapy is likely to be continued e.g. child with mechanical heart valve or repeated thromboembolic complications, as vitamin K is likely to interfere with anticoagulation with warfarin for 2 - 3 weeks.
Pregnancy and Lactation
Pregnancy
Use phytomenadione with caution during pregnancy.
The manufacturer does not recommend using phytomenadione unless the clinical benefits outweigh the risks. At the time of writing there is limited published information regarding the use of phytomenadione during pregnancy.
Lactation
Use phytomenadione with caution during breastfeeding.
The manufacturer does not recommend breastfeeding whilst taking phytomenadione unless the clinical benefits outweigh the risks. The presence phytomenadione in human breast milk and its effects on exposed infants are unknown.
Side Effects
Anaphylactoid reaction
Hypersensitivity reactions
Phlebitis
Venous irritation
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: July 2021
Reference Sources
Summary of Product Characteristics: Phytomenadione 10mg/1ml solution for injection ampoules. Cheplapharm Arzneimittel GmbH. Revised October 2020.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 06 July 2021
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