Doses - PHENOBARBITAL SODIUM, PHENOBARBITAL

Dogs:

For treatment of idiopathic epilepsy:
a) 1 - 2 mg/kg PO bid initially, then monitor and adjust dosage. Some require up to 16mg/kg/day. (Morgan 1988)
b) 5 - 16 mg/kg/day divided bid or tid (Bunch 1986)
c) Initially, 2.5 mg/kg PO bid, then monitor (some dogs may require up to 60 mg/kg/day)(Farnbach 1985)
For treatment of status epilepticus:
a) 3 - 30 mg/kg IV to effect (Morgan 1988)
b) 6 mg/kg IM or IV q6-12h as needed (Kirk 1986)
For sedation:
a) 2.2 - 6.6 mg/kg PO bid (Walton 1986)
b) Treatment of irritable bowel syndrome: 2.2 mg/kg PO bid (Morgan 1988)
c) 2 mg/kg PO q8-12h (Davis 1985a)

Cats:

Treatment of idiopathic epilepsy:
a) 8 mg - 15 mg PO once to twice daily (Morgan 1988)
b) 2.2 - 4.4 mg/kg/day divided bid or tid (Bunch 1986)
Treatment of status epilepticus:
a) 6 mg/kg IM or IV q6-12h as needed (Kirk 1986)
Sedation:
a) 1 mg/kg PO bid (Morgan 1988)
b) 2 mg/kg PO q8-12h (Davis 1985a)

Cattle:

For enzyme induction in organochlorine toxicity:
a) 5 grams PO for 3-4 weeks, off 3-4 weeks, the repeat for 3-4 more weeks. (Smith 1986)

Horses:

a) 1 - 10 mg/kg IV (Robinson 1987)
b) Loading dose of 12 mg/kg IV over 20 minutes, then 6.65 mg/kg IV over 20 minutesevery 12 hours (Duran et al. 1987)
c) 11 mg/kg PO q24 hours (Ravis et al. 1987)
d) Foals; for seizures: 20 mg/kg diluted with normal saline to a volume of 30-35 ml infused over 25-30 minutes IV, then 9 mg/kg diluted and infused as above q8h.
Recommend monitoring serum levels if possible. (Spehar et al. 1984)
Monitoring Parameters -

1) Anticonvulsant (or sedative) efficacy

2) Adverse effects (CNS related, PU/PD, weight gain)

3) Serum phenobarbital levels if lack of efficacy or adverse reactions noted. Although there is some disagreement among clinicians, therapeutic serum levels in dogs are thought to mirror those in people (15 - 40 micrograms/ml).

4) If used chronically, routine CBC's and liver enzymes at least every 6 months.
Client Information - Compliance with therapy must be stressed to clients for successful epilepsytreatment. Encourage client to give doses at the same time each day. Keep medications out of reachof children and stored in child-resistant packaging. Veterinarian should be contacted if animaldevelops significant adverse reactions (including symptoms of anemia and/or liver disease) orseizure control is unacceptable.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times - Veterinary-Approved Products: None

Human-Approved Products:

Phenobarbital Tablets 15 mg, 16 mg, 16.2 mg, 30 mg, 60 mg, 100 mg; Capsules 16 mg
Phenobarbital Elixir 15 mg/5ml in pt and UD 5, 10 & 20 ml, 20 mg/5ml in pt, gal, UD 5 and 7.5 ml
Phenobarbital Sodium for Injection 30 mg/ml, 60 mg/ml, 65 mg/ml, 130 mg/ml; in 1 ml amps, Tubex and vials
Also known as phenyethylmalonylurea or phenobarbitone. Other trade names may include:
Luminal® (Winthrop-Breon), and Barbita® (Vortech). Phenobarbital is a Class-IV controlledsubstance and is available by prescription (Rx) only.