|
Anti-Epileptic
Drugs
Over
the past 40 years new anti-epileptic drugs have become available
which enable about 75% of people with epilepsy to live seizure
free.
Why
are drugs prescribed?
The purpose of treatment is to control (not cure) epilepsy
by getting rid of all seizures or at the very least by greatly
reducing their number without producing undesirable drug side
effects. Reaching this balance may take several weeks, months
or even longer. During this period some people will experience
adverse symptoms which can make them lose heart. In a few,
control of seizures will never be fully gained, but it is
most important to continue with the treatment and to keep
a record of the number of seizures and any side effects experienced.
This record will help the doctor to make the best decision
if it becomes necessary either to change the dose of the medication
being taken or to try another drug.
Are
drugs the only treatment for epilepsy?
Anti-epileptic drugs are the mainstay of treatment for epilepsy.
Occasionally (for instance, in young children with very severe
epilepsy) a special diet may be helpful. For a few people,
surgery will be advised.
What
are the most common anti-epileptic drugs?
There are several different drugs which are commonly prescribed.
These may be referred to by the chemical name of the drug
or by the trade name (in brackets) given to the drug by the
manufacturer.
| Carbamazepine |
(Tegretol) |
| Lamotrigine
|
(Lamictal) |
| Vigabatrin
|
(Sabril)
|
| Gabapentin
|
(Neurontin) |
| Clobazam
|
(Frisium) |
| Clonazepam
|
(Rivotril) |
| Ethosuximide
|
(Zarontin) |
| Phenytoin
|
(Dilantin) |
| Primidone
|
(Mysoline) |
| Sodium
Valproate |
(Epilim) |
| Topiramate
|
(Topamax) |
| Tiagabine
|
(Gabitril) |
| Levetiracetam
|
(Keppra) |
How
do these drugs work?
Anti-epileptic drugs are absorbed into the blood system and
carried in the blood to the brain to damp down the “electrical
storms” which cause seizures. Seizure control is helped
by maintaining a roughly constant amount of the drug in the
bloodstream throughout the day and night. Missed doses reduce
the blood level and can result in more seizures. Too much
medication can surprisingly, sometimes also cause an increase
in seizures. It is important, therefore that the same amount
of drug is taken each day. If a tablet is forgotten it should
be taken immediately it is remembered and the next dose should
be taken at the usual time. This may make people feel a little
dopey for a while but will help to prevent a seizure occurring.
Extra medication should not be taken after a seizure. Anyone
having a lot of seizures, should consult their doctor, who
may adjust the dose of the anti–epileptic drug.
Do
anti–epileptic drugs have side effects?
Anti–epileptic drugs are not addictive but they sometimes
cause side effects. These can include drowsiness, weight gain,
temporary hair loss, skin rash, swollen gums, unsteadiness
and stomach upsets. These adverse effects can often be minimised.
Good dental hygiene can prevent swollen gums. Correct timing
of doses can ensure that any drowsiness occurs only at night.
Taking the medication with food can abolish stomach upsets.
Watching diet will help to prevent a gain in weight. The appearance
of a skin rash should be reported immediately to a doctor.
The benefits of good seizure control must be balanced by the
disadvantages of side effects when deciding the correct drug
and dose.
Women
who take anti–epileptic medication and wish to use some
form of oral contraception should seek medical advice as most
anti-epileptic drugs can reduce the effectiveness of the contraceptive
pill.
It
is most important that women on anti–epileptic medication
who want to have a baby consult with their doctor before becoming
pregnant as there may be a small risk to the baby from the
anti–epileptic drug treatment. Changing or reducing
the anti–epileptic drugs may be advised. A woman who
is already pregnant should discuss with her doctor the best
course of action to minimise risks to herself and to her baby.
It is important to minimise the number of seizures during
pregnancy to avoid harm to the unborn child.
Why
is a particular drug chosen?
Drugs for epilepsy come in many different forms – tablets,
coated pills, capsules, syrups and liquids. There are many
factors which can influence the doctor's choice. The type
of epilepsy, medical history and any other medication taken
must all be considered.
The
doctor must also decide which form of the drug is most suitable
for each patient to take. Syrups may be used for children
who have difficulty in swallowing tablets. Changes in the
make of the usual tablet or capsule should be avoided as the
amount of drug absorbed from each different kind of pill can
vary a little.
What
is the right amount of anti–epileptic drug to take?
The most effective amount for controlling seizures varies
from person to person. However, the correct dose of the right
drug (or in a few cases, the right combination of two drugs)
will control seizures in more that 75% of people with epilepsy.
As children grow, their dose may need to be increased. A bigger
dose may also be advised if seizures are not fully controlled.
Consult a doctor if seizure control is unexpectedly poor,
or if side effects become a problem and explore whether measuring
the drug level in the blood might be helpful.
How
often should the drug level be measured?
The frequency with which these tests should be carried out
depends on which drug is being taken, how effective it is
and whether there are side effects. The person's medical history
and the number of other drugs being taken are also relevant
factors. Because some people metabolise anti–epileptic
drugs more quickly than others, regular blood tests may be
recommended to ensure that the best dose is being prescribed.
By using a few drops of blood, tests (such as enzyme immunoassay)
can reveal quickly whether the dose is too low to be effective,
or too high and likely to cause unpl(EASANT) side effects.
If seizures are fully controlled without any side effects
whatsoever, it is usually not necessary to measure the drug
level. More frequent measurements may be necessary during
pregnancy or while breastfeeding.
How
can missed doses be avoided?
The importance of taking drugs at intervals cannot be overemphasised.
However it is not easy for everyone to remember to take the
correct dose at the same time each day, particularly if he
or she has a poor memory. The answer may be to set aside the
doses each morning so that a check can be made in the evening
that the full amount has been taken. Containers with daily
dosage helps people to take their medicine in the correct
dose and at the right time. The container is divided into
7 sections – one for every day of the week. Each section
is divided into 4 compartments allowing up to 4 daily doses
to be held. An alarm wrist watch can also be used to remind
a person when to take medication. If a dose is missed, it
should be taken as soon as it is remembered. If medication
has been missed it is very unwise to take part in potentially
dangerous activities such as driving or swimming.
If
occasional nights are spent away from home, missed doses can
be avoided by always carrying a spare dose to cover unexpected
circumstances. When holidaying abroad it is important to take
a supply sufficient to cover the period away from home, as
it may not always be possible to get the same tablets or capsules
in a foreign country. Anti-epileptic medication is sold under
different trade names in other countries and so when travelling
abroad people may find it difficult to identify the drug they
have been prescribed.
For
how long will medication be necessary?
There is no easy answer to this question! It will depend on
the individual case of epilepsy. Some people will need to
be on medication throughout their life. However, it may be
possible for a person who has been free of seizures for more
than two years to have medication slowly withdrawn under medical
supervision. Some doctors (and patients) prefer to wait for
5 years. It is important that medication is never altered
or stopped except by a doctor. The danger of changing a drug
regime without medical advice is that it may lead to prolonged
or repeated seizures which can prove dangerous.
What
other precautions need to be taken?
Most children like to mimic the activities of adults and they
may be tempted to copy a parent who takes tablets every day.
It is very important that all medication is kept out of the
reach of children.
Alcohol
interferes with the effectiveness of anti-epileptic drugs
and so it is advisable to avoid alcohol altogether or consume
it only in modest amounts.
Avoid
carrying tablets in glass bottles as these may break during
a seizure. Most chemists now supply plastic bottles.
However frustrating it may be to take medication
over a long period, it is important to comply with the prescribed
drug treatment if seizures are to be fully controlled.
Hope for the future!
Advances in the understanding of the neurochemical basis of
epilepsy and research into the development of new anti–epileptic
drugs will contribute in future to better seizure control
for even more people with epilepsy.
Original
courtesy of Epilepsy Association of Scotland
Revised by EASA June 2002
Generic
Alternatives
Recently, some epilepsy medications have become available
in generic form. While generic form has the same active ingredients
as the branded one, Epilepsy Australia Ltd does not recommend
that you switch from one to another. For some people, switching
has resulted in breakthrough seizures, increased seizures,
or new side effects. We suggest that, unless you obtain approval
from your doctor, you would be best advised to continue taking
the branded medication/s prescribed by your treating doctor.
This
information provided by the Epilepsy Association of South
Australia Inc on the Internet is designed to provide basic
information about epilepsy. It is not intended, nor does it
constitute medical or other professional advice. Diagnosis
and advice on medical care or other assessments should be
sought from a medical practitioner or suitably qualified professional.
|