POM-V
Prescription Required
Companion Animal
Epityl 60 mg Flavoured Tablets for Dogs
Active ingredient: Phenobarbital
Form
Tablet
Species
Dogs
Manufacturer
Chanelle Pharmaceuticals Manufacturing Ltd
VMD MA No.
08749/5045
What it's used for
Prevention of seizures due to generalized epilepsy in dogs.
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Paying less for Phenobarbital
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Prescription required
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Clinical information
Epityl 60 mg Flavoured Tablets for Dogs — SPC Details
Source: VMD Summary of Product Characteristics (SPC). Last updated 26 Mar 2026.
Prevention of seizures due to generalized epilepsy in dogs.
For oral administration. The required dosage will differ to some extent between
individuals and with the nature and severity of the disorder.
Tablets must be given at the same time each day and should be co-ordinated with
feeding times in a consistent manner to optimise treatment success.
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.
Revised: January 2025
AN: 01592/2024Page 5 of 8
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 µg/ml the dose may be adjusted accordingly. If seizures recur the dose may
be raised up to a maximum serum concentration of 45 µg/ml. 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.
Plasma concentrations should be interpreted in conjunction with the observed
response to therapy and a full clinical assessment including monitoring for evidence
of toxic effects in each animal.
Clinical data suggests that considerable variation in plasma concentrations of
phenobarbital may be observed in some animals. This variation may result in an
animal with a trough plasma concentration of phenobarbital below the typical
minimum therapeutic level (15 µg/ml) and a peak plasma concentration approaching
the maximum level (45 µg/ml). If the seizure control is inadequate in such animals,
care should be taken when increasing the dose as toxic levels may be reached or
exceeded. Peak and trough plasma concentrations of phenobarbital may need to be
measured in such animals. (Peak plasma concentrations are reached within
approximately 3 hours after administration).
If the seizures are not being satisfactorily controlled and if the maximum plasma
concentration of phenobarbital is about 40 µg/ml, then the diagnosis should be
reconsidered and/or a second antiepileptic product (such as bromides) should be
added to the treatment protocol.
Tablets can be divided into equal halves or quarters to ensure accurate dosing.
To break a cross scored tablet into quarters, place the tablet on an even surface with
the scored side up and apply pressure on the middle with your thumb.
To break a tablet into two halves, place the tablet on an even surface with the scored
side up, hold one half of the tablet and press down on the other half.
Revised: January 2025
AN: 01592/2024Page 6 of 8
individuals and with the nature and severity of the disorder.
Tablets must be given at the same time each day and should be co-ordinated with
feeding times in a consistent manner to optimise treatment success.
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.
Revised: January 2025
AN: 01592/2024Page 5 of 8
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 µg/ml the dose may be adjusted accordingly. If seizures recur the dose may
be raised up to a maximum serum concentration of 45 µg/ml. 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.
Plasma concentrations should be interpreted in conjunction with the observed
response to therapy and a full clinical assessment including monitoring for evidence
of toxic effects in each animal.
Clinical data suggests that considerable variation in plasma concentrations of
phenobarbital may be observed in some animals. This variation may result in an
animal with a trough plasma concentration of phenobarbital below the typical
minimum therapeutic level (15 µg/ml) and a peak plasma concentration approaching
the maximum level (45 µg/ml). If the seizure control is inadequate in such animals,
care should be taken when increasing the dose as toxic levels may be reached or
exceeded. Peak and trough plasma concentrations of phenobarbital may need to be
measured in such animals. (Peak plasma concentrations are reached within
approximately 3 hours after administration).
If the seizures are not being satisfactorily controlled and if the maximum plasma
concentration of phenobarbital is about 40 µg/ml, then the diagnosis should be
reconsidered and/or a second antiepileptic product (such as bromides) should be
added to the treatment protocol.
Tablets can be divided into equal halves or quarters to ensure accurate dosing.
To break a cross scored tablet into quarters, place the tablet on an even surface with
the scored side up and apply pressure on the middle with your thumb.
To break a tablet into two halves, place the tablet on an even surface with the scored
side up, hold one half of the tablet and press down on the other half.
Revised: January 2025
AN: 01592/2024Page 6 of 8
Do not use in animals with serious impaired hepatic function.
Do not use in animals with serious renal or cardiovascular disorders.
Do not use in dogs weighing less than 6 kg body weight.
Do not use in case of hypersensitivity to the active substance or to any other
barbiturates or to any of the excipients.
Do not use in animals with serious renal or cardiovascular disorders.
Do not use in dogs weighing less than 6 kg body weight.
Do not use in case of hypersensitivity to the active substance or to any other
barbiturates or to any of the excipients.
Dogs:
Very rare
(<1 animal / 10,000 animals treated,
including isolated reports):
Ataxia (incoordination) and sedation
Paradoxical hyperexcitability (unusually
excitable)
Polyuria (increased urination), polydipsia
(increased thirst) and polyphagia
(increased appetite)
Hepatotoxicity
Pancytopenia and/or neutropenia
Low free thyroxine (FT4) or low thyroxine
(T4)
1
: During start of therapy these effects can occur but are usually transitory and
disappear in most, but not all, patients with continued medication. Sedation and
ataxia often become significant concerns as serum levels reach the higher ends of
the therapeutic range.
: Some animals can demonstrate a paradoxical hyperexcitability, particularly after
first starting therapy. As this hyperexcitability is not linked to overdosage, no
reduction of dosage is needed.
: These effects can occur at average or higher therapeutic active serum
concentrations; these effects can be diminished by limiting intake of food.
: High plasma concentrations may be associated with hepatotoxicity.
:
Phenobarbital can have deleterious effects on stem cells from bone marrow.
Consequences are immunotoxic pancytopenia and/or neutropenia. These reactions
disappear after the treatment’s withdrawal.
: Treating dogs with phenobarbital may lower their TT4 or FT4 serum levels,
however this may not be an indication of hypothyroidism. Treatment with thyroid
hormone replacement should only be started if there are clinical signs of the disease.
Reporting adverse events is important. It allows continuous safety monitoring of a
veterinary medicinal product. Reports should be sent, preferably via a veterinarian, to
either the marketing authorisation holder or its local representative or the national
competent authority via the national reporting system. See also the package leaflet
for respective contact details.
Very rare
(<1 animal / 10,000 animals treated,
including isolated reports):
Ataxia (incoordination) and sedation
Paradoxical hyperexcitability (unusually
excitable)
Polyuria (increased urination), polydipsia
(increased thirst) and polyphagia
(increased appetite)
Hepatotoxicity
Pancytopenia and/or neutropenia
Low free thyroxine (FT4) or low thyroxine
(T4)
1
: During start of therapy these effects can occur but are usually transitory and
disappear in most, but not all, patients with continued medication. Sedation and
ataxia often become significant concerns as serum levels reach the higher ends of
the therapeutic range.
: Some animals can demonstrate a paradoxical hyperexcitability, particularly after
first starting therapy. As this hyperexcitability is not linked to overdosage, no
reduction of dosage is needed.
: These effects can occur at average or higher therapeutic active serum
concentrations; these effects can be diminished by limiting intake of food.
: High plasma concentrations may be associated with hepatotoxicity.
:
Phenobarbital can have deleterious effects on stem cells from bone marrow.
Consequences are immunotoxic pancytopenia and/or neutropenia. These reactions
disappear after the treatment’s withdrawal.
: Treating dogs with phenobarbital may lower their TT4 or FT4 serum levels,
however this may not be an indication of hypothyroidism. Treatment with thyroid
hormone replacement should only be started if there are clinical signs of the disease.
Reporting adverse events is important. It allows continuous safety monitoring of a
veterinary medicinal product. Reports should be sent, preferably via a veterinarian, to
either the marketing authorisation holder or its local representative or the national
competent authority via the national reporting system. See also the package leaflet
for respective contact details.
The decision to start antiepileptic drug therapy with phenobarbital should be
evaluated for each individual case and depends on number, frequency, duration and
severity of seizures in dogs.
Some of the dogs are free of epileptic seizures during the treatment, but some of the
dogs show only a seizure reduction, and some of the dogs are considered to be non-
responders.
Revised: January 2025
AN: 01592/2024Page 2 of 8
Special precautions for use in animals
Caution is recommended in animals with impaired hepatic and renal function,
hypovolemia, anaemia and cardiac or respiratory dysfunction. The chance of
hepatotoxic side effects can be diminished or delayed using an effective dose that is
as low as possible. Monitoring of hepatic parameters is recommended in case of a
prolonged therapy.
It is recommended to assess the clinical pathology of the patient 2-3 weeks after start
of treatment and afterwards every 4-6 months, e.g. measurement of hepatic enzymes
and serum bile acids. It is important to know that the effects of hypoxia etc. do cause
increased levels of hepatic enzymes after a seizure. Phenobarbital may increase the
activity of serum alkaline phosphatase and transaminases. These may demonstrate
non-pathological changes, but could also represent hepatotoxicity, liver function tests
are recommended. Increased liver enzyme values may not always require a dose
reduction of phenobarbital if the serum bile acids are in the normal range.
In stabilised epileptic patients, it is not recommended to switch between
phenobarbital formulations. However, if this cannot be avoided then additional
caution should be taken. This includes more frequent plasma concentration sampling
to ensure that therapeutic levels are maintained. Monitoring for increased side
effects and for hepatic dysfunction should be conducted more regularly until
stabilisation is confirmed.
Withdrawal or transition from other types of anti-epileptic therapy should be made
gradually to avoid precipitating an increase in the frequency of seizures.
The tablets are flavoured. In order to avoid any accidental ingestion, store tablets out
of reach of the animals.
Special precautions to be taken by the person administering the veterinary
medicinal product to animals
•
barbiturates should avoid contact with the product.
•
children. Take utmost care that children do not come in contact with the
product.
•
children; it may affect the developing brain and lead to cognitive disorders.
Phenobarbital is excreted in breast milk. Pregnant women, women of
childbearing age and women who are breastfeeding should avoid accidental
ingestion and prolonged skin contact with the product.
•
•
to reduce skin contact.
•
medical services of barbiturate poisoning; show the package leaflet or the
label to the physician. If possible, the physician should be informed about the
time and amount of ingestion, as this information may help to ensure that
Revised: January 2025
AN: 01592/2024Page 3 of 8
appropriate treatment is given.
•
to the open blister space and inserted back into the cardboard box.
•
evaluated for each individual case and depends on number, frequency, duration and
severity of seizures in dogs.
Some of the dogs are free of epileptic seizures during the treatment, but some of the
dogs show only a seizure reduction, and some of the dogs are considered to be non-
responders.
Revised: January 2025
AN: 01592/2024Page 2 of 8
Special precautions for use in animals
Caution is recommended in animals with impaired hepatic and renal function,
hypovolemia, anaemia and cardiac or respiratory dysfunction. The chance of
hepatotoxic side effects can be diminished or delayed using an effective dose that is
as low as possible. Monitoring of hepatic parameters is recommended in case of a
prolonged therapy.
It is recommended to assess the clinical pathology of the patient 2-3 weeks after start
of treatment and afterwards every 4-6 months, e.g. measurement of hepatic enzymes
and serum bile acids. It is important to know that the effects of hypoxia etc. do cause
increased levels of hepatic enzymes after a seizure. Phenobarbital may increase the
activity of serum alkaline phosphatase and transaminases. These may demonstrate
non-pathological changes, but could also represent hepatotoxicity, liver function tests
are recommended. Increased liver enzyme values may not always require a dose
reduction of phenobarbital if the serum bile acids are in the normal range.
In stabilised epileptic patients, it is not recommended to switch between
phenobarbital formulations. However, if this cannot be avoided then additional
caution should be taken. This includes more frequent plasma concentration sampling
to ensure that therapeutic levels are maintained. Monitoring for increased side
effects and for hepatic dysfunction should be conducted more regularly until
stabilisation is confirmed.
Withdrawal or transition from other types of anti-epileptic therapy should be made
gradually to avoid precipitating an increase in the frequency of seizures.
The tablets are flavoured. In order to avoid any accidental ingestion, store tablets out
of reach of the animals.
Special precautions to be taken by the person administering the veterinary
medicinal product to animals
•
barbiturates should avoid contact with the product.
•
children. Take utmost care that children do not come in contact with the
product.
•
children; it may affect the developing brain and lead to cognitive disorders.
Phenobarbital is excreted in breast milk. Pregnant women, women of
childbearing age and women who are breastfeeding should avoid accidental
ingestion and prolonged skin contact with the product.
•
•
to reduce skin contact.
•
medical services of barbiturate poisoning; show the package leaflet or the
label to the physician. If possible, the physician should be informed about the
time and amount of ingestion, as this information may help to ensure that
Revised: January 2025
AN: 01592/2024Page 3 of 8
appropriate treatment is given.
•
to the open blister space and inserted back into the cardboard box.
•
A therapeutic dose of phenobarbital for antiepileptic therapy can significantly induce
plasma proteins, (such as α1acid glycoprotein, AGP), which bind drugs.
Phenobarbital may reduce the activity of some drugs by increasing the rate of
metabolism through induction of drug-metabolising enzymes in liver microsomes.
Therefore special attention must be paid to the pharmacokinetics and doses of drugs
simultaneously administered. The plasmatic concentration of a range of drugs (for
example cyclosporine, thyroid hormones and theophylline) is decreased in the case
of concurrent administration of phenobarbital. Concurrent use with other drugs
having a central depressive action (like narcotic analgesics, morphinic derivatives,
phenothiazines, antihistamines, clomipramine and chloramphenicol) can increase the
effect of phenobarbital.
Cimetidine and ketoconazole are inhibitors of hepatic enzymes: concurrent use with
phenobarbital can induce an increase of serum concentration of phenobarbital.
Phenobarbital may decrease the absorption of griseofulvin. Concurrent use with
potassium bromide increases the risk of pancreatitis. Use of phenobarbital tablets in
conjunction with primidone is not recommended as primidone is predominantly
metabolised to phenobarbital.
The following drugs can decrease the convulsive threshold: quinolones, high doses
of β-lactam antibiotic, theophyllin, aminophyllin, cyclosporine and propofol for
example). Medications which may alter the seizure threshold should only be used if
really necessary and when no safer alternative exists.
plasma proteins, (such as α1acid glycoprotein, AGP), which bind drugs.
Phenobarbital may reduce the activity of some drugs by increasing the rate of
metabolism through induction of drug-metabolising enzymes in liver microsomes.
Therefore special attention must be paid to the pharmacokinetics and doses of drugs
simultaneously administered. The plasmatic concentration of a range of drugs (for
example cyclosporine, thyroid hormones and theophylline) is decreased in the case
of concurrent administration of phenobarbital. Concurrent use with other drugs
having a central depressive action (like narcotic analgesics, morphinic derivatives,
phenothiazines, antihistamines, clomipramine and chloramphenicol) can increase the
effect of phenobarbital.
Cimetidine and ketoconazole are inhibitors of hepatic enzymes: concurrent use with
phenobarbital can induce an increase of serum concentration of phenobarbital.
Phenobarbital may decrease the absorption of griseofulvin. Concurrent use with
potassium bromide increases the risk of pancreatitis. Use of phenobarbital tablets in
conjunction with primidone is not recommended as primidone is predominantly
metabolised to phenobarbital.
The following drugs can decrease the convulsive threshold: quinolones, high doses
of β-lactam antibiotic, theophyllin, aminophyllin, cyclosporine and propofol for
example). Medications which may alter the seizure threshold should only be used if
really necessary and when no safer alternative exists.
Not applicable.
5.
5.
This information is sourced from the official Summary of Product Characteristics (SPC) published by the Veterinary Medicines Directorate (VMD). It is provided for informational purposes only and does not replace professional veterinary advice. Always consult your vet before administering any medication.
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