Phenobarbital (phenobarbitone) Intravenous for Adults

Who can administer

May be administered by registered competent doctor or nurse/midwife (doctor present)

Important information

• The 200mg/ml strength is a controlled drug- must be locked in CD press
• There are numerous important interactions- check current BNF
• See local guidelines for Status Epilepticus

Available preparations

Phenobarbital 30mg in 1ml ampoule (Martindale brand)

Phenobarbital 60mg in 1ml ampoule (Martindale brand)

Phenobarbital 200mg in 1ml ampoule (Martindale brand) (controlled drug)

Reconstitution

Already in solution

• Draw up using a 5 micron filter needle
• Dilute further prior to administration

Methods of intravenous administration

Slow intravenous injection

• DILUTE each 1ml injection solution to 10ml with Water for injection ^{(ref 4)}
• Administer at a rate of 50mg to 100mg per minute ^{(ref 1)}. (Rates greater than 60mg/minute reserved for emergencies such as status epilepticus).
• Maximum rate of injection cannot exceed 100mg per minute

Dose in adults

Usual dose

• Status epilepticus: give 10mg/kg (max 1000mg ^{(ref 2,3)}) as a slow intravenous injection

Renal and Hepatic impairment

• Caution in mild to moderate impairment - avoid in severe impairment

Monitoring

• Monitor sedation score, respiratory rate, heart rate and blood pressure
• Extravasation may cause tissue damage

Further information

• Phenobarbital sodium = phenobarbitone sodium
• Injection contains propylene glycol

Storage

• Store below 25⁰C
• The 200mg/ml strength must be stored in the controlled drug press

References

Phenobarbital sodium 30mg/ml SPC 18th November 2021

Phenobarbital sodium 200mg/ml SPC 18th November 2021

1: Uptodate - downloaded 07/03/2024

2: Martindale-via Medicinescomplete - accessed online 07/03/2024

3: BNF- via Medicinescomplete- accessed online 07/03/2024

4: Injectable medicines guide- accessed online via Medusa 07/03/2024

Therapeutic classification

Anticonvulsant