Choosing a medication for epilepsy
By
Dr. George Morris
Treating seizures with medicines has many aspects and there are many
choices to be made. Treatment should stop seizures and have no limiting
side effects. When a person starts medication for seizure treatment,
approximately 2/3 will find a medication that stops their seizures and
without undue side effects.
 Steps
to finding the right epilepsy medication
- Your doctor confirms that there's a reasonable chance that your
seizures will reoccur (not a 1-time event)
- Typically you will be referred to a specialist, who will run
some tests, including an EEG and an MRI. If medication is deemed
appropriate, the specialist will prescribe one (see
below for examples).
- If the seizures continue, or if there are too many
side effects, the doctor will try a 2nd kind
of medication.
- If the seizures continue, or if there are still too many side
effects, your doctor will re-evaluate your condition, possibly run
more tests, and determine if a different treatment approach would be
more likely to work.
Issues of side effects with epilepsy medication
Unfortunately, side effects are a potential problem for medications
and we will need to be vigilant for them. The most common side effects
from seizure medications include fatigue, slowed thinking processes,
unsteadiness on one's feet and dizziness.
Seizure medications fundamentally work to suppress certain types of
brain cell activity. Those types of brain cell activity are often
involved in the seizure process, but unfortunately some of them are
present and necessary in other types of brain function. Those include
things constantly being adjusted such as thinking, alertness, our
balance and the movement of our eyes. This is why the medications that
we use for epilepsy will frequently have all of these listed as
potential side effects.
Each medication has side effects unique to that drug and depending on
which medication is appropriate, you should discuss those potential side
effects with your doctor and decide which medication is best you.
Again, the goal is to choose a medication completely eliminating
seizures, produce no limiting side effects, which is easy to take and
use, comes in many forms and is readily available. These are sometimes
challenging goals, as no ideal medicine exists. An ideal medicine taken
daily has no interactions with other medications and is easily monitored
in the blood stream. Sadly, there is no ideal medication, but those are
the features of an ideal medication, and the closer we can get to these
goals, the better the care will be.
So which epilepsy medication should I take?
We have to determine if the patient is experiencing partial seizures
or generalized seizures. Partial seizures are the most common seizure,
and many of our medications have been tested and shown to be effective
in treatment of partial seizures.
Medications are frequently described as older generation medication
or part of the newer generation of seizure medications available since
the early 1990's. Older generation medications include medications like
Dilantin (Phenytoin), Tegretol (Carbamazepine), Phenobarbital, Mysoline
(Primidone) and Depakote (Valproic Acid). These medications have been
available for decades and have been most commonly used for the treatment
of partial seizures. Many physicians have learned to use the medications
during their training and they are familiar with their many positive and
negative attributes.
Phenobarbital is the oldest of our currently used medications.
It has been available since 1912 and has the advantage of being able to
be taken once daily and remaining relatively stable in the blood stream.
It has the reputation of treating generalized tonic and clonic seizures,
but being less effective against partial seizures such as simple partial
and complex partial seizures. Phenobarbital has well recognized
blood-testing levels and has not been identified to produce any
long-term negative consequences except lowering someone's thinking
abilities and decreasing bone density. Phenobarbital's overall success
is not as good in the treatment of partial seizures as many other
medications, and its use has slowly decreased in comparison to other
medications. It is available in pill and intravenous form and can
frequently be used for short periods of time to eliminate ongoing
seizures.
Dilantin (Phenytoin) is a unique medication discovered by a
specific program looking for medications that can stop seizures. It was
the first of a long list of medications discovered by the National
Institute of Health and its program to develop seizure medications.
Dilantin may be taken once daily, making it convenient, and is effective
against partial and tonic-clonic seizures. It is available both as a
long-acting capsule, a chewable tablet for children, unstable syrup and
IV form. It has long been used as initial treatment for all types of
seizures. Dilantin has many difficulties including an unpredictable
change in the level with changes in the amount taken, an interaction
with many other medications including commonly used blood thinning
agents, aspirin, and birth control pills, a decrease in the bone density
which does not respond to more calcium and vitamin D, and potential
slowed thinking difficulties. Still Dilantin remains the most commonly
used medication for seizures due to significant familiarity to
physicians.
Tegretol (Carbamazepine) has also been available for decades
and is recognized as good treatment for partial seizures. Tegretol comes
in several forms including an elixir and sustained release capsules and
tablets known as Tegretol XR and Carbatrol. Tegretol must be taken at
least twice per day and does interact with many medications, including
some commonly used antibiotics, birth control pills and other seizure
medications. Tegretol has a pattern of producing excessive fatigue that
sometimes does not go away. Tegretol is not effective in generalized
seizures such as absence and has been known to make them worse.
Occasionally, Tegretol can lower the amount of salt in the blood stream,
although this has not been known to cause patients significant problems.
Depakote (valproic acid, divalproex) is the newest of the
older generation medications. Depakote is available in several forms
including an elixir, immediate release tablet, several sustained release
formulations and an intravenous form. Potentially the first of a group
of medications known for its ability to treat all seizure types,
Depakote has become the drug of choice for generalized types of seizures
such as absence and generalized tonic and clonic seizures, and is
effective in partial seizures. This broad spectrum of activity is a
principle strength for Depakote. Side effects include stress to the
liver, weight gain related to stimulation of the appetite, hair loss
related to fragileness of hair fibers, and a tremor of the hands.
Special attention regarding Depakote and the reproductive system has
been raised concerning its ability to produce a syndrome known as
Polycystic Ovary Syndrome leading to infertility in women. Issues about
depression of male sexuality have also been raised with Depakote.
Newer epilepsy medications
Since the medications listed above have limitations, new medications
were developed. The results of this 15-year focus resulted a number of
new medications, the new generation antiepileptic drugs. The attempt was
to produce medications with fewer side effects and fewer interactions
with other medications. The initial treatment, where the greatest
successes lie required minimizing the negative aspects of the drug so
therapy was more likely to succeed early.
Felbatol (Felbamate) is a drug which led these new generation
medications with its release in the fall of 1993. Felbatol's use is
infrequent because 2 serious, life threatening side effects were
identified: fatal hepatitis and aplastic anemia. Occurring in a small
portion of patients who were predominantly adult, these side effects
required liver and bone marrow transplants and have limited the use of
Felbatol. Side effects include headache and insomnia and it does
interact substantially with other seizure medications including Dilantin,
Tegretol and Phenobarbital. It is taken 3 times per day.
Neurontin (Gabapentin) is a drug indicated for partial onset
seizures and is taken 3 times per day. It has been shown to be an
effective add-on choice to other medications and is easily done so with
no drug interactions. Its side effects are relatively few and studies
have shown it useful in the elderly compared to Tegretol. Neurontin is
not broken down but leaves by the kidney, and so kidney function, when
it is reduced, requires adjustment of the dose. Neurontin has been found
to be useful in other conditions and most of its uses currently are in
the area of pain management.
Lamictal (Lamotrigine) was released the year after Neurontin
in 1994. It showed effectiveness in partial seizures and studies suggest
a broad spectrum of activity for both partial and generalized seizures.
Lamictal is taken twice daily and has some interactions, particularly
with Depakote. Principle benefits of Lamictal appear to be its low side
effect rate. Lamictal's principle difficulty is in the area of rash.
When the concentration in the bloodstream increases too quickly,
patients are prone to having a diffuse body rash. Some of these rashes
are allergic, but the majority are not. On a rare occasion these rashes
can be life threatening when associated with other problems, including
liver and bone marrow difficulties. Lamictal has some considerable use
outside of the U.S. and was available overseas for a number of years.
That means a significant number of birth exposures without a pattern of
significant malformation.
Topamax (Topiramate) is a drug indicated for the treatment of
partial seizures, as well as with the treatment of fairly severe
epilepsies (Lennox Gastaut). Topamax is taken twice daily and has few
interactions with seizure medications. Topamax also shares the quality
of Depakote and Lamictal in providing a benefit for multiple types of
seizures in both the partial and generalized category. Potentially one
of Topamax's largest side effects can be viewed as a positive event.
Topamax has the tendency to suppress appetite, which may be a
significant benefit. Other side effects of Topamax include a perception
of slow thinking.
Gabitril (Tiagabine) is a medication used for the treatment of
partial seizures, so its current use is limited. This is a medication
used 3 times daily that appears to have significant interactions with
other medications. In the presence of medications stimulating the liver,
such as Dilantin and Tegretol, Gabitril levels are difficult to raise.
Sedation and fatigue appear to be Gabitril's most common side effects.
Keppra (levetiracetam) was approved in 2000 and shows
effectiveness in the treatment of partial seizures. Taken twice daily,
Keppra has not been associated with interactions with other medications
and its metabolism is relatively limited. Patients find the medication
easy to take and Keppra may be increased quickly. It is effective at its
recommended starting dose. Keppra's principle side effect is a reported
difficulty with behavior disturbance. This behavior disturbance has been
seen more frequently in children but does not occur very often in any
group.
Trileptal (Oxcarbazepine) was released for the treatment of
seizures in 2000. It is chemically similar to the drug Tegretol and is
taken twice daily. Trileptal has few interactions with other
medications. It is indicated for the treatment of partial seizures.
Trileptal's principle side effect is fatigue, a lowering of blood salt
levels such as is seen with Tegretol, but is a relatively rare
phenomenon.
Zonegran (Zonisamide) is a drug that was originally released
in Japan many years ago and is indicated for the treatment of partial
seizures. The Japanese literature suggests that Zonegran may have use in
other seizure types including generalized seizures. Zonegran may be
taken once or twice daily and is generally well tolerated without
significant side effects. There is a potential cross-reaction between
individuals who are allergic to Zonegran and Sulfa antibiotics.
Zonegran's principle side effect is a potential positive one with
reductions in weight occurring in approximately 6% of patients.
Then patients say “Well, that's a lot of choices. Tell me the one I
should take.”
And I reply, we will pick the one you feel the most comfortable with
and see how it works.
|
