PHENOBARBITAL

(Phenobarb)

Standard Prescription

phenobarbital __mg IV x 1 loading dose  (__mg/kg/dose), then __mg IV __(frequency) {PRN} (__mg/kg/dose)

phenobarbital __mg PO Q__H (__mg/kg/24 hr)

Dosages

Status Epilepticus:
Children: 20 mg/kg/dose IV (Max: 1000 mg/dose).  May give an additional load of 5-10 mg/kg/dose after 10 min.

Initial Maintenance for Seizures:
< 12 years old: 2.5 mg/kg/dose PO/IV Q12H or 5 mg/kg/dose PO/IV Q24H
> 12 years old: 1.5 mg/kg/dose PO/IV Q12H or 3 mg/kg/dose PO/IV Q24H
(Usual dosing range is 3-8 mg/kg/24 hr according to serum monitoring and clinical response)

Mechanism of Action

Anticonvulsant; barbiturate.

Forms Supplied

tablet:  15 mg, 30 mg, 60 mg
elixir:  5 mg/mL - AVOID USING DUE TO ALCOHOL CONTENT
injection:
30 mg/mL ampoule
120 mg/mL ampoule
(injection contains propylene glycol and benzyl alcohol)

Comments

Avoid if allergy to aromatic hydrocarbons.

For oral dosing, it is preferable to crush tablets  instead of using liquid, as liquid is very unpalatable and contains 14% alcohol.

Adverse effects: sedation, respiratory depression (with loading dose), hyperactivity and behavior concerns in children, Stevens-Johnson syndrome.
Rapid IV injection may cause respiratory depression or hypotension. See Parenteral Manual.

Phenobarbital induces hepatic enzymes thus decreases serum levels of many drugs (e.g. anticonvulsants).

Target range is 65-170 mcmol/L.

Refer to Therapeutic Drug Monitoring in References and Supplementary (white pages in hard copy).


References

44, 336, 557

Last Edited

2022-08-25 01:45:41