What is clozapine, and how does it work (mechanism of action)?
Clozapine is an anti-psychotic
medication that works by blocking receptors in the brain for
several
neurotransmitters (chemicals that nerves use to communicate
with each
other) including dopamine type 4 receptors, serotonin type 2
receptors,
norepinephrine receptors, acetylcholine receptors, and histamine
receptors. Unlike traditional anti-psychotic agents, such as
chlorpromazine (Thorazine) and
haloperidol (Haldol) as well as
the newer
anti-psychotics, risperidone (Risperdal) and olanzapine
(Zyprexa),
clozapine only weakly blocks dopamine type 2 receptors.
What brand names are available for clozapine?
Clozaril, FazaClo, Versacloz
Is clozapine available as a generic drug?
Yes
Do I need a prescription for clozapine?
Yes
What are the uses for clozapine?
Clozapine is a medication prescribed for the management of psychotic disorders such as schizophrenia.
What are the side effects of clozapine?
The most common side effect of clozapine is drowsiness.
Dizziness is another side effect
of clozapine. Dizziness may occur in 1 of 5 persons taking clozapine. In some cases this may be due to orthostatic hypotension, a marked decrease in blood pressure that occurs when going from a lying or sitting position to a standing position. The drop in blood pressure may lead to loss of consciousness or even cardiac and respiratory arrest. This reaction is more common during the first few weeks of therapy while the dose is increasing, when drug is stopped briefly, or when patients are taking benzodiazepines such as diazepam (Valium) or other anti-psychotic drugs.
Seizures have occurred in approximately 1 of every 20 to 30 persons receiving clozapine. Patients receiving higher doses seem to be at higher risk.
QUESTION
Schizophrenia is the most disabling mental illness.
See Answer
What is the dosage for clozapine?
Clozapine is given once, twice, or three times
daily.
The dose often is increased slowly until the optimal dose is
found. The
full effects of clozapine may not be seen until several weeks
after
treatment is begun.
Which drugs or supplements interact with clozapine?
Risperidone (Risperdal) may cause an
increase
in the amount of clozapine in the blood. This could lead to an
increased
risk of side effects from clozapine.
Is clozapine safe to take if I’m pregnant or breastfeeding?
There are no adequate studies of clozapine in
pregnant women. Studies in animals suggest no important effects
on the
fetus. Clozapine can be used in
pregnancy if the physician
feels that it
is necessary.
Animal
studies suggest that clozapine is secreted in
breast milk. Therefore, women taking clozapine
should not
nurse their infants.
What else should I know about clozapine?
What preparations of clozapine are available?
Tablets (orally disintegrating): 12.5, 25, 100, 150,
and 200 mg
How should I keep clozapine stored?
Tablets should be kept below 30 C (86
F).