PHENobarbital

Disclaimer to the Online Edition

This Manual has been designed for use in the NICU at London Health Sciences Centre (LHSC), London, Ontario, Canada, and represents clinical practice at this institution. The information contained within the Manual may not be applicable to other centres. If users of this Manual are not familiar with a drug, it is recommended that the official monograph be consulted before it is prescribed and administered. Any user of this information is advised that the contributors, Editor and LHSC are not responsible for any errors or omissions, and / or any consequences arising from the use of the information in this Manual.

PHENobarbital

Indication

  • Management of neonatal seizures, and to provide sedation

Dosage Guidelines

Seizures:

  • Loading Dose: 10-20 mg/kg/dose IV; additional 5-10 mg/kg/dose q20-30 minutes to a maximum total dose of 40 mg/kg
  • Maintenance Dose: 4-6 mg/kg/day IV/ORAL given once daily or in 2 divided doses given 12 to 24 hours after loading dose
  • Hepatobiliary scintigraphy (HIDA scan): 5 mg/kg/dose ORAL q24 hours x 5-7 days before scan

Administration

  • IV intermittent slow infusion over 10-20 minutes for loading dose (rate not to exceed 1 mg/kg/min)
  • IV direct over 5 minutes (maintenance doses only)
  • ORAL

Adverse Effects

  • Hypotonia, poor feeding, sedation, respiratory depression at toxic levels
  • Irritating to veins

Comments

  • Maintain serum PHENobarbital concentration between 65-170 micromol/L.  Draw level at least 1 hour after loading dose and 0 to 2 hours before maintenance dose on day 4 of therapy.
  • PHENobarbital is an enzyme inducer, may increase metabolism of phenytoin, caffeine and corticosteroids
  • Serum half-life may range from 40 to 200 hours

Supplied As

  • 30 mg/mL injection
  • 5 mg/mL oral elixir

References:

LexiComp Sick Kids, LexiComp Pediatric and Neonatal, Neofa