PHENOBARBITAL Sodium
VIHA (South Island) IV MONOGRAPH
∗
OTHER NAMES CLASSIFICATION ELDER ALERT
Phenobarbitone Barbiturate See Cautions
INDICATIONS FOR IV USE
HEALTH CANADA APPROVED:1
• Anticonvulsant: Treatment of status epilepticus and other types of persistent convulsions.
NON HEALTH CANADA APPROVED INDICATIONS BUT SUBSTANTIATED IN THE LITERATURE
• Antenatally to prevent or minimise intraventricular haemorrhage in the LBW neonate.2
• Prophylactic seizure therapy in severe perinatal asphyxia.3
• Palliative treatment of neonatal narcotic withdrawal.4
CONTRAINDICATIONS1
Hypersensitivity or a history of idiosyncratic reaction to phenobarbital or other barbiturates.
• Severe hepatic dysfunction.
• Porphyria or a family history of intermittent porphyria.
Severe respiratory depression; including dyspnoea, obstruction, or cor pulmonale.5
•
CAUTIONS
∗ Elderly: Often have increased sensitivity; may cause marked excitement, depression, confusion, and increased risk of
barbiturate-induced hypothermia.5
• Abruptly stopping phenobarbital after prolonged therapy with high doses may result in abstinence syndrome which may
include generalised convulsions and delirium.1
DRUG INTERACTIONS:1
• Administration with other CNS depressants may result in potentiation of effects.
• Phenobarbital induces hepatic microsomal enzymes and increases the clearance of many hepatically metabolised
drugs.
• Oral anticoagulants – decreased anticoagulant effect.
• Phenytoin – decreased or increased serum concentrations of phenytoin.
• Valproate – increased serum concentrations of phenobarbital.
• Oral contraceptives – reduced effect of oral contraceptives.
PREGNANCY/BREAST FEEDING: Contact pharmacy for most recent information.
ADMINISTRATION
DIRECT INTO IV TUBING INTERMITTENT INFUSION CONTINUOUS INFUSION
MODE
YES – preferred route YES NO
WHO MAY GIVE All registered nurses All registered nurses
Loading dose: dilute in 25 mL NS.
Undiluted
Infuse over 10-15 minutes.5
ADULT
Maximum rate: 60 mg/minute.1
Max rate 100 mg/minute.7
Loading dose: See syringe pump
Undiluted
PAEDIATRIC Maximum rate: 2 mg/kg/minute up to a infusion table.
maximum 30 mg/minute6
Dilute to 10 mg/mL with NS if required.
NEONATE Maximum rate: 2 mg/kg/minute up to a Maintenance Dose: over 30 minutes
maximum 30 mg/minute6
REQUIREMENTS None
MONITORING REQUIRED
• Baseline BP, heart rate and respiratory rate, then q 15 min x 4 and until stable.
RECOMMENDED
• Assess IV site for signs of extravasation.
RECONSTITUTION
• Not required. Available as 30 mg/mL and 120 mg/mL – 1 mL ampoules.
COMPATIBILITY/STABILITY
Compatible in D5W, D10W, NS, 0.45% saline, dextrose-saline combinations and lactated Ringer’s solutions.8,9
•
• When the 30 mg/mL ampoule is diluted to 10 mg/mL with NS in a syringe or glass vial, is stable for at least 24 hours in
refrigerator.10
• Limited information on stability when diluted in PVC minibags, prepare immediately before use; do not use if a
precipitate is present.
• For drug-drug compatibility contact Drug Information.
References available on the VIHA (South Island) Pharmacy Web site (http://intranet.viha.ca/clinical_support/pharmacy/si/) Rev Jul 2003

PHENOBARBITAL Sodium
VIHA (South Island) IV MONOGRAPH
ADVERSE EFFECTS1,8
LOCAL REACTIONS
• Phlebitis, tissue irritation at injection site, necrosis if extravasated.
DERMATOLOGIC
• Skin rash, exfoliative dermatitis, erythema multiforme, Stevens-Johnson syndrome.
CENTRAL NERVOUS SYSTEM
• Sedation, drowsiness, confusion.
• Paradoxical excitement or hyperactivity.
• Respiratory depression if administered too rapidly.
CARDIOVASCULAR
• Hypotension if administered too rapidly.
HAEMATOPOIETIC
• Megaloblastic anaemia (folate responsive), agranulocytosis and thrombocytopenia.
HEPATIC
• Toxic hepatitis.
MISCELLANEOUS
• Withdrawal symptoms include seizures, diaphoresis, irritability, tremor, sleep disturbances, weight loss and anorexia.
DOSE
ADULT
• Status epilepticus: Loading dose: 10-20 mg/kg, in single or divided doses. May give an additional 5 mg/kg every 15-
30 minutes up to a maximum dose of 30 mg/kg. Maintenance dose: 1-3 mg/kg once daily or 0.5-1.5 mg/kg every 12
hours.5
• Antenatally to prevent IVH:2 10 mg/kg
ELDERLY
• Consider age-related hepatic or renal impairment.
PAEDIATRIC11
• Status epilepticus: Loading dose: 15-20 mg/kg/dose in a single or divided dose. May give an additional 5 mg/kg
every 15-30 minutes up to a maximum dose of 30 mg/kg.
Maintenance dose:
Infants: 5-6 mg/kg/day once daily or divided bid
Children 1-5 years: 6-8 mg/kg/day once daily or divided bid
Children 6-12 years: 4-6 mg/kg/day once daily or divided bid
Over 12 years: 1-3 mg/kg/day once daily or divided bid
NEONATE
• Status epilepticus:
Loading dose: 20 mg/kg/dose. May give an additional 5 mg/kg every 15-30 minutes up to a maximum dose of
40 mg/kg.12 Maintenance dose: 3-4 mg/kg/day once daily, beginning 12-24 hours after the load.12 Asphyxiated
neonates require about ½ the maintenance dose of non-asphyxiated neonates.6
• Narcotic withdrawal:4 Loading dose: 5-10 mg/kg. Maintenance dose: 2-6 mg/kg/day divided q6-8h.
RENAL IMPAIRMENT ADJUSTMENTS
• Dosing interval may need to be prolonged, monitor serum concentrations.13
HEPATIC IMPAIRMENT ADJUSTMENTS
• Dose reduction may be required, monitor serum concentrations.
HEMO/PERITONEAL DIALYSIS13
• Haemodialysis: dose after dialysis.
• CAPD: give half of the normal dose.
THERAPEUTIC DRUG MONITORING
• Pre-dose (trough) concentrations of 65-170 mcmol/L are considered therapeutic when phenobarbital is used as an
anticonvulsant.
MISCELLANEOUS
Can be given IM.1
•
• Commercially available injections should not be given SC, causes tissue irritation varying from slight redness to
necrosis. Parenteral solutions prepared from sterile powder can be given SC.8
References available on the VIHA (South Island) Pharmacy Web site (http://intranet.viha.ca/clinical_support/pharmacy/si/) Rev Jul 2003

PHENOBARBITAL - REFERENCES
1. Repchinsky C, ed. Compendium of Pharmaceuticals and Specialties. 38th ed. Ottawa, ON: Canadian Pharmaceutical
Association; 2003.203-4.
2. Barnes ER, Thompson DF. Antenatal phenobarbital to prevent or minimise intraventricular hemorrhage in the low-birth
weight neonate. Ann Pharmacother 1993; 27:49-52.
3. Hall RT, Hall FK and Daily DK. High-dose Phenobarbital therapy in term newborn infants with severe perinatal
asphyxia: A randomized prospective study with three-year follow up. J Pediatr. 1998; 132:345-8.
4. Levy M, Spiro M. Neonatal withdrawal syndrome: Associated drugs and pharmacologic management.
Pharmacotherapy 1993; 13:202-11.
5. Gahart BL, Nazareno AR. eds. Intravenous medications: a handbook for nurses and other allied health personnel. 19th
ed. St Louis; MO: Mosby Year Book; 2003:846-8.
6. Phelps SJ, ed. Pediatric injectable drugs. Teddy Bear Book. 6th ed. Bethesda, MD: American Society of Hospital
Pharmacists; 2002:310-1.
7. Treiman DM, Meyers PD, Walton NY, et al. A comparison of four treatments for generalized convulsive status
epilepticus. N Engl J Med.1998; 339:792-8.
8. McEvoy GK, ed. American Hospital Formulary Service Drug Information, Bethesda MD, American Society of Hospital
Pharmacists, 2000:1964-6.
9. Trissel LA, ed. Handbook of injectable drugs. 11th ed. Bethesda, MD: American Society of Hospital Pharmacists; 2001:
1044-8.
10. Nahata MC, Hipple TF, Strausbaugh SD. Stability of phenobarbital sodium diluted in 0.9% sodium chloride injection.
Am J Hosp Pharm 1986; 43:384-5.
11. Gunn VL, Nechyba C, eds. The Harriet Lane Handbook. A manual for pediatric house officers. 16th ed. Philadelphia,
PA: Mosby Year Book; 2002:802-3.
12. Young TE, Mangum B, eds. Neofax®: A manual of drugs used in neonatal care. 15th ed. Raleigh, NC: Acorn publishing;
2002:138.
13. Aronoff GR, Berns JS, Brier ME, et al, eds. Drug prescribing in renal failure: Dosing guidelines for adults. 4th ed.
Philadelphia, PA: American College of Physicians; 1999:93.
References available on the VIHA (South Island) Pharmacy Web site (http://intranet.viha.ca/clinical_support/pharmacy/si/) Rev Jul 2003