antipsychotic agent

antipsychotic [an″te-, an″ti-si-kot´ik]

modifying psychotic behavior.

antipsychotic agent.

antipsychotic agent any drug that favorably modifies psychotic symptoms; categories include the phenothiazines, butyrophenones, thioxanthenes, dibenzodiazepines, diphenylbutylpiperidines, dihydroindolones, and dibenzoxazepines. They are chemically diverse but pharmacologically similar. Formerly called major tranquilizer.

Antipsychotics stabilize mood and reduce anxiety, tension, and hyperactivity. They are also effective in helping to control agitation and aggressiveness. Delusions and hallucinations are often modified and may be eliminated by such an agent, but once the drug is discontinued, the delusions and hallucinations often return within a short while. Different antipsychotic agents bind to dopamine, histamine, muscarinic, cholinergic, α-adrenergic, and serotonin receptors. Blockade of dopaminergic transmission in various areas is thought to be responsible for the major antipsychotic, antiemetic effects of these agents as well as neurologic side effects. The drugs are contraindicated in patients suffering from central nervous system depression, severe allergy, Parkinson's disease, or a blood dyscrasia. There also is the possibility of drug-drug interaction when neuroleptic drugs are given concurrently with barbiturates, alcohol, tricyclic antidepressants, antihypertensives, meperidine, anticonvulsants, or levodopa.

Many antipsychotics have alarming side effects (see extrapyramidal effects); thus there must be thorough patient education and individualized adjustments in dosage. The side effects can usually be minimized by gradually increasing the dosage until the optimum for the individual is reached. Side effects such as a discomforting restlessness and agitation (akathisia), involuntary rhythmic movements of the trunk and limbs, parkinsonism, and tardive dyskinesia are often misinterpreted as symptoms of some unrelated disorder; these are often the reason for noncompliance or stopping of medication by patients. Approximately 20 per cent of the patients treated with neuroleptics for long periods develop tardive dyskinesia, a syndrome of choreoathetoid movements of the tongue, mouth, face, neck, limbs, and trunk, which may continue after the drug is stopped.

Antipsychotic agents are sometimes prescribed for conditions other than mental disorders. They can be beneficial in the control of nausea, in the treatment of intractable hiccups, in controlling the movement disorders associated with Huntington's chorea and Gilles de la Tourette's syndrome, and, in combination with other drugs, for the control of pain.

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antipsychotic agent

Major tranquilizer, neuroleptic Neuropharmacology Any drug that attenuates psychotic episodes Agents Phenothiazines, thioxanthenes, butyrophenones, dibenzoxazepines, dibenzodiazepines, diphenylbutylpiperidines Indications Management of schizophrenic, paranoid, schizoaffective and other psychotic disorders, acute delirium, dementia, manic episodes–during induction of lithium therapy, control of movement disorders—in Huntington's disease, Tourette syndrome, ballismus, intractable hiccups, severe nausea and vomiting by blocking the medulla's chemoreceptor trigger zone Adverse effects Extrapyramidal effects–dystonia, akathisia, parkinsonism, tardive dyskinesia due to blocking of basal ganglia; sedation and autonomic side effects–orthostatic hypotension, blurred vision, dry mouth, nasal congestion and constipation are due to blocking of histamic, cholinergic and adrenergic receptors