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How is epilepsy treated?
The majority of epileptic seizures are controlled through drug therapy,
particularly anticonvulsant drugs. The type of treatment prescribed will depend
on several factors, including the type of epilepsy (focal/partial versus
generalized), frequency and severity of the seizures, as well as the person's
age, overall health, and medical history. An accurate diagnosis of the type of
epilepsy (not just the type of seizure, since most seizure types occur in
different types of epilepsy) is critical to choosing the best treatment.
Drug therapy
Many drugs are available to treat epilepsy, several of which have only
recently been released.
Older, classic medications used to treat epilepsy include:
- phenytoin (Dilantin or Phenytek)
- phenobarbital
- carbamazepine (Tegretol or Carbatrol)
- primidone (Mysoline)
- ethosuximide (Zarontin)
- valproic acid (Depakene)
- divalproex (depakote, Depakote ER)
- diazepam (Valium) and various chemical derivatives such as
Klonopin, Tranxene
Newer drugs to treat epilepsy include:
- Felbamate (Felbatol)
- Gabapentin (Neurontin)
- Lamotrigine (Lamictal)
- Tiagabine (Gabitril)
- Topiramate (Topamax)
- Levetiracetam (Keppra)
- Zonisamide (Zonegran)
Many other drugs are being studied.
In general, for a given type of epilepsy there are only minor differences
among appropriate drugs. The choice is most often based on other factors
specific to each patient, such as which side effects can be tolerated by the
patient and which delivery method is acceptable.
Although the different types of epilepsy vary greatly, in general,
medications can control seizures in about 70% of epilepsy patients.
Monotherapy refers to treatment with a single drug. One of the main
principles of drug therapy in epilepsy is to use one drug in sufficient dosages
to achieve its maximum potential. (The most common treatment mistake is to treat
a patient with two drugs, each at moderate dosages. This is usually not
effective and may cause unwanted side effects.) Only when one drug proves to be
ineffective should another drug or a drug combination be tried.
In the United States, all of the recently released drugs are currently
approved to be used in combination with a "classic" drug, if
necessary, when seizures do not respond to monotherapy. Certain combinations
work better than others, but combinations of more than two drugs should be
avoided.
Side effects
Before any drug is prescribed, your health care provider will discuss with
you the potential benefits, side effects, and risks.
As is true of all drugs, the drugs used to treat epilepsy have side effects.
The occurrence of side effects depends on the dose, type of medication, and
length of treatment. The side effects worsen with higher doses but tend to be
less severe with time as the body adjusts to the medication. Anti-epileptic
drugs are usually started at lower doses and increased gradually to make this
adjustment easier.
There are three types of side effects:
- Common or predictable side effects: these are
generic, nonspecific, and dose-related side effects. They may occur with any
anti-epileptic drug because it affects the central nervous system. These
side effects include blurry or double vision, fatigue, sleepiness,
unsteadiness, and stomach upset.
- Idiosyncratic side effects: these are rare and
unpredictable allergic reactions that are not dose-related. Most often,
these side effects are skin rashes, low blood cell counts, and liver
problems.
- Unique side effects: those that are not shared
by other drugs in the same class. For example, phenytoin can cause the gums
to swell and valproic acid can cause hair loss, weight gain, and tremor.
Unique side effects should be discussed with the patient before selecting
the drug.
How the medication is prescribed
How and when the drug is taken may be an important factor in determining
which drug patients prefer. If a patient's schedule makes it difficult to take
medications several times a day, drugs that are given once daily may be
preferred.
The flexibility with which the drug can be prescribed is also important. For
example, women with seizures related to menstruation may benefit from extra
medication during their periods. Patients with nighttime seizures may benefit
from extra doses at bedtime.
Follow-up visits
It may take several months before the best drug and dosage are determined for
you. During this adjustment period, you will be carefully monitored through
frequent blood tests to measure your response to the medication. It is very
important to keep your follow-up appointments with your doctor and the
laboratory to minimize your risk for serious side effects and prevent
complications.
When seizures continue despite treatment for epilepsy, it may be because the
episodes thought to be seizures are nonepileptic. In such cases, you should get
a second opinion from a specialist and have EEG-video monitoring so the
diagnosis can be reevaluated. In specialized centers, about 15% to 20% of
patients referred for persistent, refractory, or intractable seizures ultimately
prove to have nonepileptic conditions instead.
How long treatment lasts
In some types of epilepsy, patients can be taken off treatment after a few
years, while other types of epilepsy require lifelong treatment. With few
exceptions, patients who are seizure-free for a certain period should be
reevaluated to determine whether the drug can be discontinued. How long the
seizure-free period should be varies among the types of epilepsy and is
controversial even for a given type. The decision to discontinue a medication
also depends on more than the length of the seizure-free period. These factors
include if the patient has a normal neurological examination and if the EEG and
brain scan (MRI) are/have been normal or not.
If a medication is going to be discontinued, it should be weaned gradually to
avoid triggering a seizure.
Surgery
Most patients with epilepsy do not require surgery. However, if medications are not effective after a certain period of time, surgery is an appropriate
and accepted treatment for some types of epilepsy. Of the 30% of patients whose
seizures cannot be controlled with drugs, approximately half (more than 100,000
in the United States) may be candidates for epilepsy surgery. However, only
about 3,000 epilepsy surgeries are performed annually.
Before surgery is considered as an appropriate treatment, a comprehensive
presurgical examination is performed. This evaluation is performed to ensure
that the operation will likely improve the seizures and that it will not cause
damage to essential functions such as speech, movements, vision, sensation, and
memory. The evaluation requires prolonged EEG-video monitoring and other tests
to pinpoint the exact location of the injured brain cells causing the seizures.
The location of the damaged cells determines whether the surgery can be
performed and what technique is used.
The multidisciplinary evaluation is directed by a neurologist who specializes in
epilepsy (an epileptologist). A patient's eligibility for surgery is determined
jointly by the neurosurgeon, neuroradiologist, neuropsychologist, social worker,
and epileptologist. The decision to have the surgery is made jointly by the
patient and the epileptologist after carefully reviewing the risks and benefits
of the procedure.
Surgery is most commonly performed to treat partial epilepsy, since only one
area of the brain is involved. During surgery, the area of the brain that
triggers the seizures is removed. After surgery, some patients will be
completely free of seizures; others may still require medication, but the
seizures will be better controlled. A few patients may need additional surgery.
Other surgical approaches are reserved for specific types of epilepsy and are
most often performed in young children. One approach is to remove a large part
of one side of the brain (a hemispherectomy), or to disconnect various regions
of the brain (functional hemispherectomy, corpus callosotomy)
Other treatment options
The ketogenic diet has received much attention over the last decade. It may
be effective for treating certain types of severe epilepsy. However, the diet requires careful planning and may be difficult to follow, so it is usually not
feasible in older children or adults. The diet is usually started in the
hospital, and when successful, it is usually maintained for 2 to 3 years.
Another treatment modality involves electrical stimulation of the vagus
nerve. This treatment requires minor surgery to implant a stimulator (like a
pacemaker), which is about the size of a deck of cards. The stimulator is placed
under the skin in the upper chest. This treatment appears to be effective for
seizures that do not respond well to medications alone. The degree of
effectiveness of the vagal nerve stimulator is approximately the same as any of
the new medications. Vagal nerve stimulation almost never eliminates all
seizures, and almost all patients need to continue taking medications after the
stimulator has been placed. This treatment was approved by the FDA in 1997.
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