Antipsychotic poisoning in young children: a systematic review.

The aim of this review was to determine the spectrum and severity of effects of unintentional antipsychotic poisoning in children. A computerised literature search of MEDLINE (1966 to February 2005) and EMBASE (1980 to February 2005) was undertaken. The Internet was searched using URL: www.google.com. The proceedings of the North American Congress of Clinical Toxicology (NACCT) and the European Association of Poisons Centres and Clinical Toxicologists (EAPCCT) were hand searched. All cases of unintentional antipsychotic (all classes) poisoning in children aged 0-6 years were included. The data extracted included the age, weight, antipsychotic, dose, clinical effects, treatment and outcomes. The toxic dose was estimated as the lowest dose causing objective adverse effects.Sixty-eight reports were identified. Few contained all of the required information. Most of the case series included multiple antipsychotics with limited information on individual drugs or all ages with limited paediatric information. For most antipsychotics the ingestion of one tablet caused symptoms that were sometimes severe and usually lasted from 1 to 3 days. Extrapyramidal symptoms (EPS) were often delayed for up to 12-24 hours. Chlorpromazine caused CNS depression, hypotension and miosis; EPS and cardiac effects were rare, and the toxic dose was estimated to be 15 mg/kg. Haloperidol caused drowsiness (rarely coma) and over one-half of patients had neuromuscular effects (mainly EPS), with a toxic dose estimated at 0.15 mg/kg. Thioridazine caused CNS depression and potentially cardiac effects, with a toxic dose of 1.4 mg/kg. Atypical antipsychotics caused significant CNS depression (except risperidone); EPS were less common. Toxic doses were clozapine 2.5 mg/kg, olanzapine 0.5 mg/kg and aripiprazole 3 mg/kg. EPS responded to anticholinergic drug treatment. In summary, unintentional antipsychotic ingestion in children can cause severe effects that last 1-3 days, often with one tablet. Children potentially ingesting a toxic dose or who are symptomatic should be considered for assessment in hospital. Most cases resolve with good supportive care. Toxic doses are only estimates that are based on limited data and should be used with caution until prospective studies are undertaken.

Delayed dystonia following pimozide overdose in a child.

BACKGROUND: Pimozide overdose has rarely been reported in children. In adults, pimozide intoxication may cause seizures, extrapyramidal and anticholinergic effects, hypotension, QTc prolongation and torsades de pointes. We report dystonia, hypotension and drowsiness following pimozide ingestion in a child. CASE REPORT: An alert 18-month-old presented to hospital 40 minutes after ingesting up to 6 mg (0.5 mg/kg) of pimozide. Vital signs: BP 91/62 mmHg, HR 130/min, RR 26/min, temperature 97.2 degrees F (36.2 degrees C). She received gastric lavage and activated charcoal. One hour later, her QTc interval was 420 msec, HR 150. She remained asymptomatic until 12 hours post-ingestion, when she developed drooling, tongue thrusting and drowsiness. BP was 75/40, HR 150, QTc 440 msec. BP increased to 95/50 after a bolus of normal saline. Her dystonia subsided over the next 12 hours without treatment. Drowsiness and tachycardia persisted until 40 hours post-ingestion. QTc interval at this time was 370 msec. Patient recovered without sequelae. CONCLUSION: Pimozide overdose in children may be associated with delayed onset of symptoms, including dystonia.

Case report: reversible QT prolongation with torsades de pointes in a patient with pimozide intoxication.

Pimozide is a diphenylpiperidine neuroleptic with well characterized cardiovascular side effects including QT prolongation. So far, life-threatening cardiac arrhythmias, in particular torsades de pointes, have not been described in patients treated with pimozide. The authors describe a patient in whom torsades de pointes developed after the ingestion of 800 mg pimozide as a suicide attempt. After intravenous treatment with lidocaine and magnesium, the patient recovered completely and the QT interval had normalized 5 days after the intoxication. Potential mechanisms leading to torsades de pointes in patients treated with pimozide are discussed.

Pimozide: a review of its pharmacological properties and therapeutic uses in psychiatry.

Pimozide 1-(1-[4,4-bis(4-fluorophenyl)butyl]-4-peperidinyl)-2-benzimidazolone, is the first of a new series of psychotropic drugs, the kiphenylbutylpiperidines. It is advocated for once-daily use as maintenance therapy in chronic schizophrenia and for the treatment of psychic and functional disorders induced by personality traits. Published data suggest that in chronic schizophrenia, pimozide 4 to 6mg daily is indistinguishable from maintenance doses of chlorpromazine, fluphenazine, flupenthixol, perphenazine, or thioidazine. Patient groups have usually been to small to allow statistically significant differences to be apparent, but in some trials pimozide was significantly superior to trifluoperzine and to haloperidol. On present evidence, pimozide has no place in the hyperactive, aggressive type of patient or in treating the acute phase of schizophrenia, probably because of its relative lack of sedative properties compared with many antipsychotic drugs. The incidence and severity of extrapyramidal reactions with pimozide are low, but suitably designed controlled studies are needed to determine whether its use leads to a reduction in the requirement for antiparkinsonian medication. In anxious patients, pimozide seems to offer no advantages over currently available anxiolytic agents, either in terms of efficacy or incidence of side-effects. Claims for a specific effect against anxiety associated with psychosis or disturbed personality traits remain unproven.