Anti-Psychotic – Drugs, Side Effects, Action

Important terms

• Psychoses These are severe psychiatric illness with serious distortion of thought, behaviour, capacity to recognise reality and of perception (delusions and hallucinations). There is inexplicable misperception and misevaluation; the patient is unable to meet the ordinary demands of life.

• Neuroses These are less serious; ability to comprehend reality is not lost, though the patient may undergo extreme suffering. Depending on the predominant feature, it may be labelled as:

Pathophysiology of mental illness

It is not clear, though some ideas have been formed, e.g. dopa minergic overactivity in the limbic system may be involved in schizophrenia and mania, while monoaminergic (NA, 5-HT) deficit may underlie depression.

Treatment is empirical, symptom oriented and not disease specific. However, it is highly effective in many situations. Depending on the primary use, the psychotropic drugs may be grouped into:

1. Antipsychotic (neuroleptic, ataractic, major tranquilizers) useful in all types of functional psychosis, especially schizophrenia.
2. Antimanic (mood stabiliser) used to control mania and to break into cyclic affective disorders.
3. Antidepressants used for minor as well as major depressive illness, phobic states,

ANTIPSYCHOTIC DRUGS (Neuroleptics)

These are drugs having a salutary therapeutic effect in psychoses.

1. Phenothiazines :- Chlorpromazine Triflupromazine Thioridazine Trifluoperazine Fluphenazine
2. Butyrophenones :-Haloperidol Trifluperidol Penfluridol
3. Thioxanthenes:-Flupenthixol
4. Other heterocyclic:-Pimozide Loxapine
5. Atypical antipsychotics:-Clozapine Risperidone Olanzapine Quetiapine Aripiprazole Ziprasidone Amisulpride Zotepine

Antipsychotics used for!!

The following conditions:

• Schizophrenia:- Schizoaffective disorder most commonly in conjunction with either an antidepressant (in the case of the depressive subtype) or a mood stabilizers (in the case of the bipolar subtype).
• Bipolar disorder (acute mania and mixed episodes) may be treated with either typical or atypical antipsychotics, although atypical antipsychotics are usually preferred because they tend to have more favourable adverse effect profile.
• Psychotic depression In this indication it is a common practice for the psychiatrist to prescribe a combination of an atypical antipsychotic and an antidepressant as this practice is best supported by the evidence.

Adverse effect

• Sedation
• Headaches
• Dizziness
• Diarrhea
• Anxiety
• Extrapyramidal side effects
• Dystonia, an abnormal muscle contraction
• Hyperprolactinemia (are for those treated with clozapine, quetiapine and aripiprazole) which can cause: – Galactorrhoea, the unusual secretion of breast milk.
• Gynaecomastia, abnormal growth of breast tissue

Mechanism of action

Antipsychotic drugs such as haloperidol and chlorpromazine tend to block dopamine D2 receptors in the dopaminergic pathways of the brain.

This means that dopamine released in these pathways has less effect. Excess release of dopamine in the mesolimbic the prefrontal cortex, and excess dopamine bipolar disorder.

• Chlorpromazine is a phenothiazine that is used to treat psychotic disorders such as adults to treat nausea and vomiting, schizophrenia or manic-depression in adults. Chlorpromazine is also used in anxiety before surgery, chronic hiccups, acute intermittent porphyria, and symptoms of tetanus.
• Trifluoperazine use is in severe emesis and severe Hiccups. Due to its potential side effects it is not gold standard in antiemetic therapy.
• Fluphenazine Medication Fluphenazine, sold under the brand names PROLIXIN among others. It is used in the treatment of chronic psychoses such as schizophrenia, and appears to be about equal in effectiveness to low-potency antipsychotics like chlorpromazine.
• Thioridazine (Mellaril or Melleril) is a first generation antipsychotic drug belonging to the phenothiazine drug group and was previously widely used in the treatment of schizophrenia and psychosis.
• Trifluoperazine, sold under a number of brand names, is a typical antipsychotic primarily used to treat schizophrenia. It may also be used short term in those with generalized anxiety disorder but is less preferred to benzodiazepines. It is of the phenothiazine chemical class.
• BUTYROPHENONE is a chemical compound; some of its derivatives (called commonly butyrophenones) are used to treat various psychiatric disorders such as schizophrenia, as well as acting as antiemetics.
• Haloperidol, marketed under the trade name HALDOL, it is used in the treatment of schizophrenia, tics in Tourette syndrome, mania in bipolar disorder, nausea and vomiting, delirium, agitation, acute psychosis, and hallucinations in alcohol withdrawal.
• Trifluperidol ,it has general properties similar to those of haloperidol, but is considerably more potent by weight, and causes relatively more severe side effects, especially tardive dyskinesia and other extrapyramidal effects.
• Penfluridol is a highly potent, first generation diphenylbutylpiperidine antipsychotic.
• THIOXANTHENE is a chemical compound in which the oxygen atom in xanthene is replaced with a sulfur atom. It is also related to phenothiazine. Several of its derivatives are used as typical antipsychotics in the treatment of schizophrenia and other psychoses.
• Pimozide it has a high potency compared to chlorpromazine. On a weight basis it is even more potent than haloperidol. It also has special neurologic indications for Tourette syndrome and resistant tics.
• Loxapine, sold under the trade names LOXITANE and ADASUVE (inhalation only) among others, is a typical antipsychotic medication used primarily in the treatment of schizophrenia. The drug is a member of the dibenzoxazepine class and structurally related to clozapine.
• Clozapine, sold under the brand name CLOZARIL among others, is an atypical antipsychotic medication. It is mainly used for schizophrenia that does not improve following the use of other antipsychotic medications. In those with schizophrenia and schizoaffective disorder it may decrease the rate of suicidal behavior.
• Amisulpride is an antiemetic and antipsychotic medication used at lower doses intravenously to prevent and treat postoperative nausea and vomiting; and at higher doses orally and intramuscularly to treat schizophrenia and acute psychotic episodes.
• Risperidone is used to treat schizophrenia, bipolar disorder, or irritability associated with autistic disorder.

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