Epiphen
Active substance
ATC code
Species
Dog.
Indications
Phenobarbital is an antiepileptic agent for use in the control of epilepsy in the dog.
Dose 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.
For accuracy of dosing, dogs under 6kg should commence therapy with Epiphen Solution. Tablets are not intended to be subdivided.
Adverse reactions
Ataxia, somnolence, listlessness and dizziness may occur rarely at the start of treatment. In some cases, these effects may persist for the entire duration of treatment.
A paradoxical hyperexcitability may occur rarely, particularly after first starting therapy. As this hyperexcitability is not linked to overdosage, no reduction of dosage is needed.
Sedation and ataxia may very rarely become significant concerns as serum levels reach the higher end of the therapeutic range.
Polyphagia, polyuria and polydipsia have been reported rarely, but these effects are usually transitory and disappear with continued medication.
Hepatotoxicity may develop very rarely at doses over 20mg/kg/day or when serum Phenobarbital levels are high (see special precautions for use)
Phenobarbital can have deleterious effects on stem cells from bone marrow, immunotoxic pancytopenia and/or neutropenia and anaemia may occur very rarely.
Superficial necrolytic dermatitis may occur after administration of phenobarbital very rarely.
Hypoalbuminaemia was rarely reported. Phenobarbital may increase the activity of serum alkaline phosphatase and transaminases. These may demonstrate nonpathological changes, but could also represent hepatotoxicity, so liver function tests are recommended (see section 4.5).
In very rare cases, change of behaviour such as aggression was reported.
If adverse effects are severe, it is recommended to decrease the daily dose.
The frequency of adverse reactions is defined using the following convention:
- very common (more than 1 in 10 animals treated displaying adverse reaction(s))
- common (more than 1 but less than 10 animals in 100 animals treated)
- uncommon (more than 1 but less than 10 animals in 1,000 animals treated)
- rare (more than 1 but less than 10 animals in 10,000 animals treated)
- very rare (less than 1 animal in 10,000 animals treated, including isolated reports)
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| Art. Nr. | 08007/4067 |
| EAN | 3605874237575 |
