In this section
This information is provided as general information about the
drug treatment of epilepsy. The information is not a substitute for
proper medical advice. Consult your doctor for any questions or
concerns you have about you or your child's medication. For urgent
information about incorrect dosing or overdosage please contact
your doctor, pharmacist or the Poisons Information Centre 13 11 26 Nationwide Australia.
Antieplieptic medications do not cure epilepsy, but rather
attempt to prevent seizures. Strictly speaking, these medications
are antiseizure or anticonvulsant, rather than antiepileptic.
Antiepileptic medications do not alter the underlying problem
predisposing to seizures. People with epilepsy are prescribed
antiepileptic medications with the aim of decreasing the number,
severity, and/or duration of seizures. While seizure freedom is the
ideal outcome of treatment, seizures can still occur while taking
Antiepileptic medication is usually prescribed for children with
recurrent seizures, ideally after a specific epilepsy syndrome
diagnosis is made and the risk of subsequent seizures is known.
However, there are instances when a doctor may prescribe medication
after a single seizure (eg. when the risk of subsequent seizures is
great) and when medication is not prescribed after several seizures
(eg. when seizures are a minor and self-limiting problem). Other
factors taken into consideration when prescribing antiepileptic
medication include the child's age, other medical conditions,
findings on an EEG, other medications the child is taking, and
potential for side effects.
Normal brain function involves "communication"
between millions of nerve cells (neurons). At any one time,
there are nerve cells which are resting, exciting or inhibiting
other nerve cells. A nerve cell is made up of a cell body and
branches called axons and dendrites which join other neurons at
junctions called synapses. Electrical signals are sent from the
cell body along the axon to the synapse, these electrical signals
being the result of ion (sodium, potassium, calcium) currents
across channels in the nerve cell membrane. Chemical signals
(neurotransmitters) pass across synapses between neurons.
Neurotransmitters cross the synaptic gap between neurons and fix to
receptor points of the adjoining neuron. Some neurotransmitters
function to excite the joining neuron (eg. glutamate) to send a
further electrical signal. Other neurotransmitters function to
inhibit the joining neuron (eg. GABA) and inhibit electrical
signals passing down that neuron. It is by these electrical and
chemical pathways that the millions of neurons within the brain
communicate and function normally.
Seizures occur when there is an imbalance within these
excitatory and inhibitory circuits in the brain, either throughout
the brain (generalised epilepsy) or in a localised part of the
brain (focal epilepsy), such that neurons "fire off" in an abnormal
Antiepileptic medications work in different ways to prevent
seizures, either by decreasing excitation or enhancing inhibition.
Specifically, they act by either:
As the specific mechanisms that cause epilepsy are mostly
unknown, drugs with specific mechanisms of action directed at the
underlying "epileptic processes" have not yet been developed.
An antiepileptic medication is swallowed by mouth
and passes directly to the stomach. Once in the stomach the
medication is absorbed into the blood stream where it is then
circulated to the brain, via the liver, and acts on the nerve
cells. As the drug is circulating in the blood, it is gradually
removed by either the liver breaking it down (metabolism) or the
kidneys filtering it out (excretion). Some drug metabolites are
active and produce either beneficial antiepileptic effects or
adverse side effects. Most commonly prescribed antiepileptic
medications are removed from the blood at a rate that allows twice
daily dosing to maintain adequate blood levels. Some drugs are
removed more quickly than others and have to be taken 3 or 4 times
throughout the day, whilst others are removed slowly and can be
taken once each day.
For some medications, children need to have blood tests to
determine the level in the bloodstream (eg. phenytoin,
phenobarbitone, carbamazepine). These blood levels are generally
measured before a dose is due. Not all antiepileptic medications
need to be monitored with drug levels, as there is not a good
correlation between drug level and effect.
The dose of medication prescribed is determined by the child's
age and weight. Young children and adolescents have greater rates
of drug clearance and are often prescribed doses per kilogram of
body weight greater than an adult would receive.
In an emergency situation, such as status epilepticus, some
antiepileptic drugs can be given directly into the blood stream,
into the rectum, nose or buccal to act very quickly to control
The choice of medication and how each is prescribed is a
specialist area of paediatrics and child neurology. Prescription of
antiepileptic medication is only done by a doctor with knowledge of
antiepileptic medication and epilepsy in children. General
principles that doctors follow when prescribing antiepileptic
medications in children include:
Always follow your doctors
instructions about medication.
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All medications have the possibility of causing side effects.
There are three main types of antiepileptic medication side
Please refer to the specific drug information provided with your
medication for a more detailed list of side effects. As
numerous side effects are listed against all medications, your
doctor should help you understand which are the more common or
potentially serious side effects to look out for. It is
important to contact your doctor if you are worried about these or
other side effects. For urgent information please contact your
doctor, pharmacist or the Poisons Information Centre 13 11 26 Nationwide Australia.
Always read the consumer information and follow instructions
from your doctor and pharmacist carefully. Any concerns or
questions should be discussed with your doctor or pharmacist. It is
important to take the exact dose that is prescribed by the doctor
at approximately the same time each day. It may take many days or
weeks to reach the dose that is most effective. The dose that your
doctor is building up to may not be the maximum tolerated or
prescribed dose for that medication.
Establishing a regular routine can help to avoid medication
being missed. Taking medication with meals or using a medication
dosette may help. Maintaining supplies and current prescriptions
can avoid running out of medication at the last minute. If a dose
is missed it can generally be taken as soon as you remember. Do not
double up on doses. It is advisable not to take the missed
dose if it is close to the next one. Keep a record of doses that
have been missed.
Only take medication that is prescribed by your doctor. Never
try another person's medication. What medication may control one
person's seizures may not be suitable for another. Many drugs
interact with each other, so it is very important to always seek
the advice of a doctor or pharmacist before taking any other
medications with antiepileptic medications. It should also be
noted that many "complementary medicines" interact with
Vomiting and diarrhoea can affect the amounts of medication that
are absorbed from the gut into the blood stream. This can result in
low circulating levels of antiepileptic medication. Also, viral
illnesses are a common trigger for seizures in children with
epilepsy. If vomiting occurs within minutes of taking the
medication, another dose can be administered. Seek medical advice
if vomiting and diarrhoea persist.
It is recommended to keep a seizure diary to
record seizures as this helps monitor effectiveness of medication.
The diary can also be used to record missed medication, side
effects, illnesses and doctors visits.
Some medications require regular blood level monitoring by a
simple blood test. These medications include phenytoin,
phenobarbitone and sometimes carbamazepine; your doctor will
determine if these are necessary.
Teaching children how to swallow tablets and capsules
Concurrent use of antiepileptic medication with hormonal
contraceptives (the pill) may cause the contraceptive to be
ineffective. Higher dose oral contraceptives and additional
non-hormonal (barrier methods) are often recommended but you should
seek specific advice from your family doctor, neurologist,
gynaecologist or Family Planning Centre.
Many complex circumstances exist during pregnancy for women with
epilepsy. It is recommended that women taking antiepileptic
medication receive pre-pregnancy counselling and discuss their
individual circumstances with their doctor.
The Australian Centre of Clinical Neuropharmacology has
developed a voluntary Australian Epilepsy Pregnancy Register of women who become pregnant whilst taking
antiepileptic medication. The primary aim of the register is to
determine the incidence of adverse foetal outcomes resulting from
pregnancies in Australian women who were taking antiepileptic
medications. The secondary aims are to identify if certain
antiepileptic medications, or combinations of medications, are
associated with a higher overall incidence of foetal outcomes or
specific types of malformations. As well we will try to identify
other risk factors that may increase the risk of malformations
Effects on ability to drive and use
machinesSome antiepileptic medications can cause drowsiness, sleepiness,
incoordination and slowed reaction time, especially when the
medication is being introduced or the dose is being increased.
Effects on individuals should be assessed prior to driving or using
Effects when taken with alcoholIf alcohol is taken in combination with antiepileptic medication,
extra sedative effects can occur. Also, alcohol increases the
likelihood of seizures.
For an up-to-date listing of medications
permitted in sport, refer to the Australian Sports Anti-Doping Authority.