98 Section 2/ Drugs Acting on CNSNEWER COMPOUNDSLOXAPINE
It is the antipsychotic agent resembling
chlorpromazine in pharmacological actions.
It is used in manifestation of psychotic
disorders, acute and chronic paranoid
schizophrenia.
CLOZAPINE
It is an atypical neuroleptic drug. It in-
terferes with binding of dopamine at D1 and
D2 receptors in CNS. It produces few ex-
trapyramidal symptoms.
After oral administration it is rapidly and
almost completely absorbed. The absorption
is not affected by food and it is almost com-
pletely metabolised in liver. The metabolites
are much less potent and less toxic.
Adverse effects include nausea, vomit-
ing, heartburn, constipation, diarrhoea,
agranulocytosis, eosinophilia, postural hy-
potension, tachycardia, angina, headache,
sedation, dizziness, syncope, seizures, hy-
perthermia, neuroleptic malignant syn-
drome, weight gain and sexual dysfunction.
May lead to myocarditis.
It is indicated in all types of schizophre-
nia including resistant cases not responding
to conventional antipsychotics and chronic
schizophrenia.
PIMOZIDE
It is a diphenylbutylpiperidine deriva-
tive. Pimozide causes low incidence of dys-
tonic reactions.
It acts by blocking dopaminergic recep-
tors and has weak a-adrenergic and cholin-
ergic blocking activity. It has long duration
of action (several days) after a single dose.
Adverse effects include mania, insomnia,
nervousness, fatigue, drowsiness, nausea,
extrapyramidal reactions and irritability.
It is used in the treatment of acute and
chronic schizophrenia and manic excite-
ment.ZUCLOPENTHIXOL
Zuclopenthixol is a thioxanthene of high
potency with general property similar to the
chlorpromazine. It has a piperazine side-
chain.
Adverse effects include extrapyramidal
symptoms and on prolonged administra-
tion, occasionally tardive dyskinesia, hypo-
thermia (occasionally pyrexia), drowsiness,
apathy, pallor, nightmares, insomnia, de-
pression, agitation, EEG changes, endocrine
effects such as menstrual disturbances, ga-
lactorrhoea, gynaecomastia, impotence and
weight gain, alterations in liver function.
It is used in the maintenance therapy of
schizophrenia.ANTIANXIETY DRUGS
(MINOR TRANQUILLIZERS)
Anxiety is a emotional feeling of fear along
with discomfort and uneasiness. Antianxi-
ety drugs are used to control the symptoms
of anxiety without affecting the other men-
tal and physical functions of the body. They
are classified as in table 2.5.2.BENZODIAZEPINES
The detailed pharmacology of all the
benzodiazepines used in anxiety disorders