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Lamotrigine
(brand name Lamictal) is a mood stabilizer which was first developed to
treat epilepsy and was later found to help bipolar disorder. Lamotrigine is
unique among mood stabilizers in that it is more effective for the
depressed than the manic mood swings.
If lamotrigine works well, it
should produce a sense of well-being by relieving symptoms of depression,
mania and sometimes anxiety. It takes several weeks for the full effects to
come on. Though it is usually well tolerated, lamotrigine has one important
side effect: a rash (see below; read “Preventing rashes” before
starting the medicine).
How does it work?
Lamotrigine
stabilizes nerves in the brain by blocking sodium channels, which are
involved in nerve cell firing.
What types are available and how is it taken?
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Regular Tabs
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25, 100, 150 and 200mg;
non-scored tabs.
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Chewable Tabs
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2mg, 5mg and 25mg (can be
liquefied in water or juice).
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Dosing
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Treating doses range from
100-200mg per day, but lamotrigine needs to be increased very slowly to
help prevent the rash (also, read “Preventing Rashes” below
before starting it). We will
decide the safest dose schedule for you; two typical dose schedules are
below:
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Regular dosing
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Dosing for
children, teens and people taking Depakote
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Week 1: 25mg/day
Week 2: 50mg/day
Week 3: 75mg/day
Week 4: 100mg/day
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Week 1-2: 25mg every other day Week 3-4: 25mg/day
Week 5-6: 50mg/day
Week 7-8: 75mg/day
Week 9-10: 100mg/day
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How to take it, Missed doses
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Lamotrigine is taken once a
day in the morning or night, with or without food. If you miss a dose, take it as soon as
possible. However, if it is almost time for your next dose, skip the
missed dose and go back to your regular dosing schedule. Do not double up
on doses. If you have missed your dose for a week or more, call me before
restarting it; we may need to restart at a lower dose and raise it slowly
again.
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How long will I need to take it for?
Lamotrigine can be used both
to prevent and treat the symptoms of bipolar disorder, so how long you are
on it will depend on the reasons you are using it. Lamotrigine is not addictive.
What side effects can I expect?
Lamotrigine
is usually well tolerated.
Approximately 10% of people have side effects that make them want to
stop the medicine; the most common ones are dizziness, headache, lack of
coordination, nausea, diarrhea, itching, blurred or double vision, vivid
dreams, and drowsiness. Side effects
can also improve by lowering the dose.
Serious
side-effects:
Lamotrigine
has one rare but serious side effect: a skin rash (called Stevens-Johnson
syndrome), which occurs in approximately 2 in 1,000 people. This is a
blistering reaction in the skin and mouth that can be disfiguring or life-threatening. Approximately 1 in 100 people will
develop a non-serious rash on lamotrigine, but since it is unknown what
kind of rash will become serious, you need to stop
lamotrigine and call me (722-7266), or go to your local emergency room if
you get any kind of rash. The rash
usually occurs during the first two months of treatment.
Sometimes
this serious reaction can occur without a rash. The other signs to look for are fever,
swollen lymph nodes, and puffiness of the face; stop the medicine and
follow the emergency instructions above if these occur.
Lamotrigine has also been
associated in a few reports of aplastic
anemia (a serious drop in the blood cells that are necessary to fight
infection, clot blood and deliver oxygen to the body) and in severe hypersensitivity reactions
which have included severe problems in multiple parts of the body. These reactions were very rare and occurred
in people with severe seizure disorders; these reactions are not known to
occur in bipolar disorder.
Preventing
rashes:
To prevent false-alarms while you’re at risk for
the rash (the first 2-4 months of treatment, or when doses are raised), do
the following to reduce risks of non-serious rashes:
- Avoid new soaps, detergents or skin products
(bring your soap with you if traveling).
- Avoid exposure to plants or animals that might
cause rashes (e.g. poison ivy).
- Try not to start lamotrigine if you have signs of
infection (e.g. cough, fever, diarrhea, flu).
Precautions
Lamotrigine may increase the effects of alcohol and
medicines that make you drowsy, including antihistamines (benadryl), cold
and allergy medicines; sedatives, tranquilizers, or sleeping medicine;
prescription pain medicine or narcotics; barbiturates; medicine for
seizures; muscle relaxants; or anesthetics, including some dental
anesthetics.
Since
lamotrigine may cause blurred vision, drowsiness or discoordination, Make sure you know how you react to it before
you drive, use machines, or do anything else that could be dangerous if you
are not alert, well-coordinated, or able to see well.
Pregnancy
and Breast-feeding: lamotrigine has not been studied in
pregnant women and there is evidence from animal studies that it may be
harmful to the fetus (Pregnancy Category C). Lamotrigine does pass into
breast milk, which in theory could cause problems for nursing babies.
Children: children
younger than 16 are at higher risk for serious skin rashes with
lamotrigine.
Older
adults: lamotrigine is removed from the body
more slowly in people after age 65, so lower dosages may be needed.
Non-Caucasian
Race:
lamotrigine can be removed from the body more slowly (by about 25%) and
may need an adjustment to the dose.
Medical problems:
- Heart disease: it is not clear if patients who
have problems with heart rhythms will have increased problems while
taking lamotrigine.
- Kidney or Liver disease or: higher blood levels of
lamotrigine may occur.
- Thalassemia: lamotrigine may cause your body to
stop making or to make fewer red blood cells.
Drug Interactions
There are two
mood stabilizers which interact with lamotrigine: carbamazepine (Tegretol),
which can lower lamotrigine levels, and valproate (Depakote), which can
increase its levels and the risk of a rash.
Other medications that can lower
lamotrigine levels include:
- Olanzapine
(Zyprexa; by 20%), Oral Contraceptives (by about 50%), Phenobarbital
(Luminal), Phenytoin (Dilantin), Primidone (Mysoline),
Rifampin.
Storage
- Keep
out of the reach of children.
- Store
away from heat and direct light.
- Do
not store in the bathroom, near the kitchen
sink, or in other damp places. Heat or moisture may cause the medicine
to break down.
- Do
not keep outdated medicine or medicine no longer needed. Be sure that
any discarded medicine is out of the reach of children.
Updated 9/21/4 by Chris Aiken,
M.D.
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