Critical Care Trauma Centre

PHENOBARBITAL SODIUM

Name: PHENOBARBITAL SODIUM 
Classification: barbiturate; anticonvulsant
  • sedative
  • used to treat seizures that fail to respond to phenytoin

This is a Tier 3 drug and only approved physicians may order

Dose:
  • For Refractory Status Epilepticus:
    • Loading Dose: 10 - 15 mg/kg IV (reduce to 5-10 mg/kg IV for patients with hypotension). Administer slowly over 1 hour.
    • Infusion:  Start at 0.5 - 1 mg/kg/hour and titrate slowly to a maximum dose of 0.5 - 10 mg/kg/hour as required to maintain a desired interburst interval (period of suppression on a continuous EEG
Administration: IV direct:
  • undiluted OR diluted to 10mL with sodium chloride 0.9%, dextrose 5% or Ringer's Lactate 
  • Do not administer faster than 50 mg/minute
IV Infusion: 
1000 mg in 250 mL (4 mg/mL) sodium chloride 0.9%, dextrose 5% or Ringer's Lactate
Adverse Effects:
  • respiratory depression
    • laryngospasm, bronchospasm, angioedema
    • apnea especially if administered too rapidly
  • bradycardia
  • hypotension and cardiovascular depression; caution in patients with cardiovascular disease
  • solution is very alkaline; extravasation may produce tissue necrosis and thrombophlebitis
  • intra-arterial injection may cause severe pain with reactions ranging from transient pain to gangrene
  • skin rashes
Drug Interactions:
  • phenobarbital + beta adrenergic blockers (eg. propranolol) = decreased beta blocker effect
  • phenobarbital + haloperidol = decreased haloperidol effect
  • phenobarbital + meperidine = increased meperidine CNS depression (increased production of normeperidine)
  • phenobarbital + theophylline = decreased theophylline effect
Monitoring Therapy:
  • respiratory rate and breath sounds; rapid IV administration may cause laryngospasm or bronchospasm
  • blood pressure
  • continuous HR and rhythm
  • ICP and CPP if indicated
  • Continous EEG
  • Mechanical ventilation with continuous End Tidal CO2 and pulse oximetry monitoring
  • serum concentrations, therapeutic 65-170 uM/L (pre-dose), toxic >215 uM/L administration site 
CCTC Protocol:
  • May be administered IV direct or by IV infusion by a nurse in Adult Critical Care provided that an MD administered the first dose
  • Administer via Central Venous Line
  • Continuous infusions must be administered by infusion device and the pump library must be enabled


Lynne Kelly, Pharmacist, CCTC
Brenda Morgan, Clinical Nurse Specialist, CCTC
Last Update: October 11, 2018