Definition Assignment by Andrea Raven
Introduction:
In this writing exercise, a relatively complex term used in the pharmaceutical
industry is defined for use by non-technical readers. Parenthetical, sentence and
expanded definitions of the term clozapine indicate different levels of detail in the
content of each definition. The objective of this exercise is to understand how
audience and purpose determine how complex terms are defined.
The Situation:
My employer asked me to prepare a Fact Sheet describing the properties of
clozapine which is an antipsychotic drug used to treat schizophrenia.
Audience and Use Profile:
The Fact Sheet describes the properties of clozapine, how it operates, how it
should be used and its side effects. The document will be distributed to
pharmacy customers who have been prescribed clozapine and request more
information about the drug.
Parenthetical Definition:
Clozapine (an atypical antipsychotic drug) is used to treat schizophrenia (a
mental illness that causes disturbed or unusual thinking, loss of interest in life,
and strong or inappropriate emotions).
Sentence Definition:
Clozapine is an antipsychotic medication used in the treatment of refractory
schizophrenia, a form of schizophrenia which does not respond to other drug
treatments.
Expanded Definition:
CLOZAPINE FACT SHEET
What is Clozapine?
Discovered in the mid 1970’s, Clozapine is an atypical antipsychotic drug which
has a unique ability to treat both positive (delusions/hallucinations) and negative
(social/emotional withdrawal) symptoms of refractory schizophrenia (Belmaker &
Bersudksy, 2003). It is used in cases where other drug treatments have not
been successful.
How is it Different from Older Typical Antipsychotic Drugs?
Clozapine does not have the same side effects as typical antipsychotics which
could cause extrapyramidal symptoms (spasms, rigidity and tremors), interfere
with the function of the ovaries, increase risk of osteoporosis and induce
irregular, jerky movements. (Üçok & Gaebel, 2008).
How does Clozapine Work?
Clozapine’s exact method of action is unclear. It changes the activity of certain
natural substances called dopamine and serotonin in the brain. Seeman (2004)
suggests that atypical antipsychotics such as clozapine bind loosely at the brain’s
D2 dopamine receptors and rapidly bounce off them allowing normal
transmission of chemicals that brain cells need to communicate with each other.
This distinguishes clozapine from older typical antipsychotics that bind tightly to
dopamine receptors and bounce off more slowly. Seeman (2004) believes this
difference between the typical and atypical antipsychotics allows clozapine to
work without having side effects such as extrapyramidal symptoms (EPS) which
commonly occurred when typical antipsychotics were used. Figure 1 (click to
enlarge) illustrates Seeman’s theory of how clozapine works in the brain.
Figure 1. Binding of typical and atypical antipsychotics to D2 dopamine
receptors.
Source: Adapted from Macpherson,
E., https://neurowiki2012.wikispaces.com/Treatment+and+Management
What are the Side Effects of Clozapine?
Despite its effective treatment of schizophrenia, Clozapine is used as a last
resort to treat this disease because a possible side effect of its use
is agranulocytosis (an acute condition of low white blood cells which supresses a
person’s immune system). This creates a high risk of serious infection and in
some cases results in death (Üçok & Gaebel, 2008).
Other side effects may include: severe constipation, hyper-salivation, central
nervous system issues, seizures, cardiac problems, weight gain and diabetes
(Üçok & Gaebel, 2008).
How is Clozapine Taken?
A strict blood work regime must be followed by patients taking this drug, in order
to minimize its most dangerous side effects. Pharmacists can only dispense the
drug if regular blood tests indicate the patient’s white blood cell count is not
affected.
Clozapine is taken in solid tablet form, with or without food. It should be taken at
the same time daily to keep levels of the drug in the bloodstream constant. If a
dose of the medication is missed for two days or more, the patient should see a
doctor immediately as the side effects of sudden withdrawal from Clozapine are
significant.
How Long Does It Take To Work?
It can take several weeks for patients to notice a reduction or elimination of
hallucinations (hearing voices), delusions (distressing thoughts not based in
reality), and thought disorder (difficulty thinking clearly). Clozapine does not
cure schizophrenia; it manages it. Therefore, the drug is usually taken on a long
term basis.
Works Cited:
Belmaker, R. H., and Bersudsky, Y. (2003). Mechanism of atypicality of
antipsychotic drugs. Progress in Neuro-Psychopharmacolgy & Biological
Psychiatry. 27(7): 1067-1069.
Seeman, P. (2004). Atypical Antipsychotics: Mechanism of Action. Focus. 2(1):
48-58.
Üçok, A., and Gaebel, W. (2008). Side effects of atypical antipsychotics: a brief
overview. World Psychiatry. 7(1): 58-62.