Encyclopedia of Health and Medicine

antipsychotic medications 363
conduct electrical impulses among neurons) in the
brain. Most antipsychotic medications target
DOPAMINE, a NEUROTRANSMITTER that is integral to
the functions of thought, reasoning, memory,
emotion, and mood. Though researchers do not
know what causes psychotic disorders, they
believe the ways in which the brain produces and
uses dopamine are key factors.
Conventional
chlorpromazine
haloperidol
perphenazine
prochlorperazine
thiothixene
trifluopromazine
Novel (Atypical)
aripiprazole
loxapine
olanzapine
risperidone
ANTIPSYCHOTIC MEDICATIONS
fluphenazine
mesoridazine
pimozide
thioridazine
trifluoperazine
clozapine
molindone
quetiapine
ziprasidone
Therapeutic Applications
Doctors prescribe antipsychotic medications to
treat psychotic disorders such as severe BIPOLAR
DISORDER, schizophrenia, personality disorders, dissociative
disorders, OBSESSIVE–COMPULSIVE DISORDER
(OCD), and severe MANIA. Often a therapy regimen
includes several medications that address various
symptoms. Treatment with antipsychotic medications
requires regular and close follow-up to monitor
therapeutic effect as well as potential side
effects.
Risks and Side Effects
Antipsychotic medications have numerous risks
and side effects, many of which are drug specific.
The most serious is neuroleptic malignant syndrome
(NMS), a constellation of symptoms that
may occur at any time during treatment with
antipsychotic medications, although it is more
likely to develop with sudden high doses. NMS
follows a predictable course, starting with MUSCLE
rigidity with high FEVER, confusion, and disorientation.
Rapid intervention is necessary to stop the
antipsychotic medications, reduce the fever, and
provide appropriate medical support. Without
such intervention, there is high probability that
NMS will be fatal.
Dopamine, the primary target of most antipsychotic
medications, is also the primary neurotransmitter
for NERVE impulses that regulate
voluntary movement. Conventional antipsychotics
have a broad base of effects in regard to their
actions on dopamine receptors. Because of this
nonspecific activity, these drugs have high risk
for causing neuromuscular complications (druginduced
movement disorders). The most serious of
these complications is tardive dyskinesia, a condition
of involuntary, rhythmic, repetitious movements.
Tardive dyskinesia is a particular risk
with phenothiazines and sometimes persists even
after stopping the medication. Other possible
neuromuscular side effects include tremors and
rigidity.
Novel, or atypical, antipsychotic medications
target specific dopamine receptors found in
greater numbers in the regions of the brain that
regulate cognitive and emotional functions.
Though novel antipsychotics can cause neuromuscular
side effects with prolonged, high-dose use,
the side effects are likely to be both less severe and
temporary. A rare complication associated with
clozapine is severe agranulocytosis, a precipitous
drop in the number of white BLOOD cells called
granulocytes. Granulocytes are essential for
immune function. Because of the potential for this
complication, people who take clozapine must
have blood tests once a week for the duration of
treatment plus four weeks after treatment ends to
monitor their white blood cell counts.
Both conventional and novel antipsychotics
interact with numerous medications, prescription
as well as OVER-THE-COUNTER (OTC) DRUGS and some
interact with foods. The longer a person takes
antipsychotic medications, the greater the risk for
complications or side effects. It is essential that the
prescribing psychiatrist regularly and frequently
evaluate the effectiveness of treatment and make
adjustments as possible to reduce risk. For most
people who have serious psychotic disorders, the
QUALITY OF LIFE that medications make possible
clearly outweighs their potential side effects.
See also ANTIANXIETY MEDICATIONS; ANTIDEPRESSANT
MEDICATIONS; DISSOCIATIVE DISORDER; ELECTROCONVUL-
SIVE THERAPY (ECT); GRANULOCYTE; PSYCHOTHERAPY.