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Clozapine is a unique
antipsychotic that has helped over 225,00 people
with schizophrenia, schizoaffective disorder and bipolar disorder. Clozapine is an
important treatment option because it tends to help even when other
medicines did not work. Like other antipsychotics, clozapine
helps take away voices and other frightening symptoms. After recovery from these symptoms, clozapine helps people to stabilize their mood and
regain their motivation and concentration.
These benefits have allowed many people to live independent lives
for the first time.
Clozapine is
the only medication proven to help people with schizophrenia who have not responded to antipsychotic medication. It is also one of few medicines that reduces suicide attempts and self-injury.
Unlike other antipsychotics, clozapine has few or no side effects involving the
muscles, such as restlessness, stiffness, shakiness, and cramps. Clozapine can
improve muscle problems, such as tardive dyskinesia, that are caused by other antipsychotics.
Patients treated with clozapine have
reported the following positive effects (remember, not everyone will
experience all of these improvements):
- Ability to
concentrate improves
- Ability to enjoy
previous activity returns
- Improved
relationships
- Ability to
participate in counseling, vocational training, or other activities of
daily life improves
- Ability to live
independently improves
- A decrease in
suicidal behavior
With all these benefits, why doesn’t everyone with
schizophrenia take clozapine? The answer is that clozapine
can cause a serious side effect called “agranulocytosis,”
which means a loss of the white blood cells that fight infection. This problem is very rare, and happens in
about 1 in 100 people who take clozapine. To help
prevent it, people taking clozapine need to have
their blood drawn regularly to check the white blood count.
How should this medicine be used?
Clozapine comes as a tablet to take by
mouth. It usually is taken one to three times a day. Follow the directions
on your prescription label carefully, and ask your doctor or pharmacist to
explain any part you do not understand. Take clozapine
exactly as directed. Do not take more or less of it or take it more often
than prescribed by your doctor.
The amount of clozapine you take may need
to be adjusted, especially during the first few weeks. You will have weekly
blood tests while taking clozapine and for 4
weeks after stopping it. Initially, you will receive only a 1-week supply
of this medication at a time.
Continue to take clozapine even if you feel
well. Do not stop taking clozapine without
talking to your doctor, especially if you have taken large doses for a long
time. Your doctor probably will want to decrease your dose gradually. This
drug must be taken regularly for a few weeks before its full effect is
felt.
What special precautions should I follow?
Before taking clozapine,
- tell
your doctor and pharmacist if you are allergic to clozapine
or any other drugs.
- tell your doctor and
pharmacist what prescription and nonprescription medications you are taking,
especially those listed in the IMPORTANT WARNING section,
anticoagulants ('blood thinners') such as warfarin
(Coumadin), benztropine (Cogentin),
carbamazepine (Tegretol), cimetidine (Tagamet), dicyclomine
(Bentyl), erythromcyin
(E.E.S., E-Mycin, others), medication for
high blood pressure, phenytoin (Dilantin),
pain relievers such as codeine, selective serotonin reuptake
inhibitors (SSRIs) such as fluoxetine (Prozac, Sarafem)
and fluvoxamine (Luvox), trihexyphenidyl
(Artane), and vitamins.
- in addition to the
condition listed in the IMPORTANT WARNING section, tell your doctor if
you have or have ever had blood disorders; heart, kidney, or liver
disease; depression; epilepsy; problems with your urinary system or
prostate; glaucoma; irregular heartbeat; problems with your blood
pressure; or blood problems caused by clozapine.
- tell
your doctor if you are pregnant, plan to become pregnant, or are
breast-feeding. If you become pregnant while taking clozapine, call your doctor.
- if
you are having surgery, including dental surgery, tell the doctor or
dentist that you are taking clozapine.
- you
should know that this drug may make you drowsy.
- remember
that alcohol can add to the drowsiness caused by this drug.
- tell
your doctor if you use tobacco products. Cigarette smoking may
decrease the effectiveness of this drug.
What should I do if I forget a dose?
If you take clozapine several times a day,
take the missed dose as soon as you remember it and take any remaining
doses for that day at evenly spaced intervals. However, if you remember a
missed dose when it is almost time for your next scheduled dose, skip the
missed dose.
If you take clozapine once a day at bedtime
and do not remember it until the next morning, skip the missed dose. Do not
take a double dose to make up for a missed one.
What side effects can this medication cause?
As with any medication, certain side effects are associated with clozapine. Some of the side effects that have been
reported when therapy is started disappear with time or after the healthcare
professional adjusts the dosage. In some cases the side effects require
treatment. The healthcare professional, or another member of the treatment
team, can give advice on how to recognize potential side effects and what
to do about them.
In addition to agranulocytosis (the most
serious side effect associated with clozapine),
the following side effects have been reported:
- Seizures or
convulsions: The higher the dosage, the greater the risk of seizures.
Also, people who have had seizures in the past are more likely to have
them with clozapine. If a person suffers a
seizure, he or she should tell their healthcare professional at once.
- Fast or irregular
heartbeat: If this happens, the dosage may be reduced, or this side
effect may be treated with another medication.
- Myocarditis
(an inflammation of a muscle in the heart): The risk is greatest
during the first month of clozapine therapy.
- Orthostatic
hypotension (a fall in blood pressure when suddenly standing up): The
risk is highest when treatment with clozapine
is started.
- Other less serious
reported side effects are drowsiness, heavy drooling, headache,
constipation, fever, fatigue, nausea, and weight gain. Because
healthcare professionals are familiar with these and other possible
side effects, they can offer advice on relieving them.
Although side effects from clozapine are
not common, they can occur. Tell your doctor if any of these symptoms are
severe or do not go away:
- drowsiness
- dry mouth
- weight gain
- excessive saliva
production
- diarrhea
- constipation
- restlessness
- headache
If you experience any of the following symptoms or those listed in
the IMPORTANT WARNINGS section, call your doctor immediately:
- tremor
- seizures or
convulsions
- difficulty
urinating or loss of bladder control
- confusion
- eye pain
- shakiness
- chest pain
- severe muscle
stiffness
- sore throat
- unusual bleeding or
bruising
- upset stomach
- vomiting
- loss of appetite
- yellowness of the
skin or eyes
Clozapine can cause high blood sugar
(hyperglycemia). If you experience any of the following symptoms, call your
doctor immediately:
- thirst
- dry mouth
- tiredness
- flushing
- dry skin
- frequent urination
- loss of appetite
- trouble breathing
What storage conditions are needed for this medicine?
Keep this medication in the container it came in, tightly closed, and
out of reach of children. Store it at room temperature and away from excess
heat and moisture (not in the bathroom). Throw away any medication that is
outdated or no longer needed. Talk to your pharmacist about the proper
disposal of your medication.
In case of emergency/overdose
In case of overdose, call your local poison control center at
1-800-222-1222. If the victim has collapsed or is not breathing, call local
emergency services at 911.
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