Neuroleptic Poisoning

Basics

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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