Prepared by : Hamad Emad Dhuhayr

Typical antipsychotic

› General concepts › Mechanism of action› Indications › Side effects› SPECIFIC ANTIPSYCHOTIC MEDICATIONS› Conclusion

Contents-:

›They have an equal or greater affinity for D2

receptors than for 5-HT2 receptors›Antagonism of D2 receptors in mesolimbic pathways

suppress the positive symptoms of Schezophrenia.›Blockade of D2 receptors in the basal ganglia is

responsible for parkinsonian and other extrapyramidal side effects of anti psychotic drugs

General concepts for typical

› The exact mechanism of action of antipsychotic drugs is unknown.

› According to the dopamine theory of schizophrenia, positive symptoms are the result of an overactivity in the mesolimbic dopamine pathway.

› first-generation antipsychotics are D2 antagonists. As a result, they reduce dopaminergic neurotransmission in the four dopamine pathways.

Mechanism of action

› Psychomotor Agitation: High potency APMs (Haloperidol) are used because injections are available

› Schizophrenia: Treatment of choice for acute psychotic episodes & for prophylaxis

› Other Psychotic Disorders: Treatment of Psychoses & Cognitive disorders due to general medical conditions & substances, delusional disorder, brief psychotic disorder,

Indications

› schizophreniform disorder & other rarer psychotic disorders› ! Mood Disorders: Treatment of Agitation & Psychosis during

mood episodes› ! Sedation: Useful when Benzodiazepines are contraindicated

(specially in older› patients) or as an adjunct during anesthesia› ! Movement Disorders: Treatment of choice for Huntington

disease & Tourette disorder

Side effects

TARDIVE DYSKINESIA (TD)

› Characterized by irreversible Choreoathetosis & other involuntary movements

› Movements often occur first in the tongue or fingers & later involve the trunk

› Movements disappear during sleep

› Etiology may be a form of “chemical denervation hypersensitivity”, which is caused by chronic Dopamine blockade in the basal ganglia

› Older Patients who take high doses of older APMs for long periods of time are at highest risk & movements gradually worsen with continued use

› o Treatment

› ! Stop older APMs

› ! Use newer APMs

› ! Chlorpromazine (Older Low-Potency D2)› o Highly Sedating. More Hypotension. More Anticholinergic effects› o Low frequency of EPS› o Few remaining indications for primary selection› ! Haloperidol (Older High-Potency D2)› Less Sedating. Less Hypotension. Less Anticholinergic effects› High frequency of EPS› Remain useful for Rx of Acute Agitation, especially via IM injections› Long acting (Haloperidol: once q 4 wks & Fluphenazine: once q 2 wks)

SPECIFIC ANTIPSYCHOTIC MEDICATIONS

› First-generation antipsychotics are also known as: typical antipsychotics, conventional or classic antipsychotics and dopamine antagonists.

› FGAs reduce dopaminergic neurotransmission in the four dopamine pathways by blocking D2 receptors.

› FGAs differ in potency, not effectiveness. – High-potency: haloperidol, fluphenazine– Mid-potency: perphenazine, loxapine– Low-potency: chlorpromazine

Conclusion

References

&