Neuroleptic Poisoning



  • Neuroleptics (antipsychotics) are used for a wide range of conditions:
    • Schizophrenia and other psychotic disorders
    • Major depression
    • Posttraumatic stress disorder
    • Agitation
    • Dementia in the elderly
    • Attention-deficit hyperactivity disorder
    • Autism and behavioral problems in children
    • Eating disorders
    • Antiemetic
    • Migraine headaches
  • Most widely used classification system categorizes them as either typical or atypical antipsychotics
  • Acute overdose:
    • Symptoms usually mild to moderate
    • CNS and cardiovascular symptoms predominate
  • Toxicity may also develop in therapeutic dosing, manifesting as extrapyramidal syndromes:
    • Symptom onset ranges from hours to years depending on syndrome
    • Acute dystonia
    • Akathisia
    • Parkinsonism
    • Neuroleptic malignant syndrome (NMS)
    • Tardive dyskinesia
    • Of these NMS is the most serious


  • Primary mechanism of action is varying degrees of dopamine antagonism as well as potentially serotonergic, histaminic, muscarinic, and α-adrenergic blockade
  • May also antagonize sodium and potassium channels
  • Typical neuroleptics (phenothiazines, butyrophenones) usually have stronger antagonism of dopaminergic receptors, these include:
    • Haloperidol (Haldol)
    • Chlorpromazine (Thorazine)
    • Prochlorperazine (Compazine)
    • Thioridazine (Mellaril)
    • Fluphenazine (Prolixin)
    • Promethazine (Phenergan)
    • Droperidol (Inapsine)
    • Hydroxyzine (Atarax)
  • Atypical neuroleptics usually have weaker dopaminergic antagonism and moderate serotonergic antagonism, these include:
    • Asenapine (Saphris)
    • Aripiprazole (Abilify)
    • Clozapine (Clozaril)
    • Risperidone (Risperdal)
    • Serdolect (Serlect and Serdolect)
    • Olanzapine (Zyprexa)
    • Quetiapine (Seroquel)
    • Ziprasidone (Geodon)

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