Amounts to be administered and administration route
The required dosage will differ to some extent between individuals and with the nature and severity of the disorder.
Dogs should be dosed orally, starting with a dose of 2-5mg per kg bodyweight per day. The dose should be divided and administered twice daily.
Steady state serum concentrations are not reached until 1-2 weeks after treatment is initiated. The full effect of the medication does not appear for two weeks and doses should not be increased during this time.
If seizures are not being controlled, the dosage may be increased by 20% at a time, with associated monitoring of serum Phenobarbital levels. The Phenobarbital serum concentration may be checked after steady state has been achieved, and if it is less than 15 mg/l the dose may be adjusted accordingly. If seizures recur the dose may be raised up to a maximum serum concentration of 40 mg/l (see special precautions for use). High plasma concentrations may be associated with hepatotoxicity. Blood samples could be taken at the same time to allow plasma Phenobarbital concentration to be determined preferably during trough levels, shortly before the next dose of Phenobarbital is due.
Epiphen 30mg tablets
For accuracy of dosing, dogs under 6kg should commence therapy with Epiphen Solution. Tablets are not intended to be subdivided.
Epiphen 60mg tablets
For accuracy of dosing, dogs under 6 kg should commence therapy with Epiphen solution, and dogs between 6 and 12 kg should commence therapy with either Epiphen solution or Epiphen 30mg tablets.
Tablets are not intended to be subdivided.