Fatalities associated with therapeutic use and overdose of atypical antipsychotics

Olanzapine overdose in children and adolescents: two case reports and a review of the literature

Although the atypical antipsychotic olanzapine is increasingly being used in child and adolescent psychiatry, reports of olanzapine overdose in this young population are scarce. We report on two cases of adolescents who attempted suicide with an overdose of olanzapine: (1) A 14-year-old female ingested 275 mg olanzapine, which produced the highest reported nonlethal serum level (1503 ng/mL) and caused somnolence, agitation (acutely), and extrapyramidal symptoms (EPS; after 54 hours) but no major clinical complications. The serum olanzapine level dropped to 129 ng/mL within 48 hours; and (2) a 17-year-old male ingested 400 mg olanzapine, the highest reported nonlethal dose of olanzapine in adolescents, which produced respiratory suppression requiring intubation and mechanical ventilation; he recovered after 3 days. Based on clinical monitoring and postmortem data, the 2 patients survived the ingestion of high doses of olanzapine. We also provide a review of the literature, encompassing all reported cases of olanzapine overdose in children and adolescents and discuss symptoms, diagnosis, and treatment options, based on pharmacokinetic and pharmacodynamic considerations.

Suspected clozapine poisoning in the UK/Eire, 1992–2003

OBJECTIVE

Toxicological analyses are often performed to investigate suspected poisoning, but the interpretation of results may not be straightforward. We studied suspected poisoning cases 1992-2003 where blood clozapine and N-desmethylclozapine (norclozapine) were measured in order to assess the relationship of these parameters to outcome.

METHODS

Samples were referred from clinicians, pathologists/coroners, or via the Clozaril Patient Monitoring Service (CPMS, Novartis). Information was gathered from clinical, post-mortem, or coroners' reports.

RESULTS

There were seven fatal [five male, two female; median (range) age 28 (24-41) year] and five non-fatal [four male, one female; median age 35 (26-41) year] clozapine overdoses. The median post-mortem blood clozapine and norclozapine concentrations were 8.2 (3.7-12) and 1.9 (1.4-2.4)mg/L, respectively [median clozapine:norclozapine ratio 4.4 (2.9-5.1)]. The median plasma clozapine and norclozapine concentrations (first or only sample) were 3.9 (1.7-7.0) and 0.40 (0.30-0.70)mg/L, respectively [median clozapine:norclozapine ratio 7.6 (5.3-18)] in the remainder. These overdoses were in patients who were poorly or non-adherent to clozapine, or who had taken tablets prescribed for someone else. In 54 further people who died whilst receiving clozapine [38 male, 16 female; median age 41 (22-70) year], the median post-mortem blood clozapine and norclozapine concentrations were 1.9 (0-7.7, n = 43) and 1.4 (0-6.0, n = 39)mg/L, respectively [median clozapine:norclozapine ratio 1.5 (0.4-7.6, n = 38)]. The median post-mortem increase in blood clozapine and norclozapine as compared to the most recent ante-mortem measurement was 489 (98-5,350)% and 371 (139-831)%, respectively [median sample time before death 14 (0-30, n = 21) days].

CONCLUSION

Clozapine poisoning cannot be diagnosed on the basis of blood clozapine and norclozapine concentrations alone. The analysis of ante-mortem blood specimens collected originally for white cell count monitoring and the blood clozapine:norclozapine ratio may provide additional interpretative information.

Fatal poisoning with antipsychotic drugs, England and Wales 1993-2002

Prescription of atypical antipsychotics has increased in recent years. There have also been changes in the guidance on using older drugs, particularly the restriction in the use of thioridazine. We analysed deaths due to poisoning involving antipsychotics in England and Wales, 1993-2002, by age, sex, intent, and agents involved. We also studied antipsychotic prescribing in the community and poisoning deaths in England. Deaths attributed to adverse reactions in the course of normal treatment were not studied because these deaths are not classified as 'poisonings'. The number of deaths involving antipsychotics increased from around 55 per year 1993-1998 to 74 in 2000, and then fell to 53 in 2002. Around 25% of deaths had a verdict of accidental death and in about 60% of deaths a verdict of suicide or an open verdict was recorded. There were no deaths involving thioridazine in 2002, following its removal from use in 2001. However, the number of deaths associated with atypicals, most notably olanzapine and clozapine, has increased. Age-specific death rates were highest in those aged 30-39 and 40-49 years, and were very low in those aged under 20 and 70 or over. Death rates in males were greater than in females. For many drugs the proportion mentions either alone or with ethanol, was 25-45%, but for clozapine and olanzapine such mentions totalled 65-69%. Deaths per million prescriptions (clozapine excluded) were highest for quetiapine (31.3 per million), chlorpromazine (29.4 per million) and thioridazine (15.5 per million).

Toxicology and overdose of atypical antipsychotic medications in children: does newer necessarily mean safer?

PURPOSE OF REVIEW

Atypical antipsychotic medications (second-generation antipsychotics) have been increasingly used in the treatment of a number of psychotic disorders since their introduction in 1988, with the newest medication introduced in 2002. Justification for their use includes claims of equal or improved antipsychotic activity over first-generation antipsychotics, increased tolerability, and decreased side effects. However, there are still significant adverse effects and toxicities with this class of medications. Toxicologic exposures and fatalities associated with atypical antipsychotics continue to increase in the United States, with 32,422 exposures and 72 deaths in 2003. There have also been Food and Drug Administration warnings in the past year about how some atypical antipsychotics have been marketed to minimize the potentially fatal risks and claiming superior safety to other atypical antipsychotics without adequate substantiation, indicating the toxicologic potential of these agents may be underestimated.

RECENT FINDINGS

Continued research to evaluate adverse effects and tolerability of atypical antipsychotics compared with first-generation antipsychotics and each other is reviewed. This article also reviews the pharmacodynamics, pharmacokinetics, and drug interactions with these medications. New therapeutic monitoring recommendations for this class of medications have also been proposed. Finally, clinical toxicity in overdose and management are reviewed.

SUMMARY

While new atypical antipsychotic medications may have a safer therapeutic and overdose profile than first-generation antipsychotic medications, many adverse and toxic effects still need to be considered in therapeutic monitoring and overdose management.

Quetiapine. A review of its use in the management of schizophrenia

Quetiapine (Seroquel), a dibenzothiazepine derivative, is an atypical antipsychotic with demonstrated efficacy in acute schizophrenia. In short-term, randomised, double-blind trials, it was usually more effective than placebo, and was generally effective against both positive and negative symptoms. Overall, quetiapine (up to 750 mg/day) was at least as effective as chlorpromazine (up to 750 mg/day) and had similar efficacy to haloperidol (up to 16 mg/day) in patients with acute schizophrenia in randomised, double-blind trials; it was at least as effective as haloperidol 20 mg/day in patients with schizophrenia unresponsive or partially responsive to previous antipsychotic treatment. Improvements in overall psychopathology and positive and negative symptoms with quetiapine (up to 800 mg/day) were similar to those with risperidone (up to 8 mg/day) or olanzapine (15 mg/day) [interim analysis]. Efficacy was maintained for at least 52 weeks in open-label follow-up studies in adult and elderly patients. Quetiapine improved cognitive function versus haloperidol, and depressive symptoms and hostility/aggression versus placebo. Quetiapine is well tolerated. It is associated with placebo-level incidence of extrapyramidal symptoms (EPS) across its entire dose range, appears to have a low risk for EPS in vulnerable patient groups (e.g. the elderly, adolescents or patients with organic brain disorders) and has a more favourable EPS profile than risperidone. Irrespective of dose, quetiapine, unlike risperidone and amisulpride, does not elevate plasma prolactin levels compared with placebo, and previously elevated levels may even normalise. Quetiapine appears to have minimal short-term effects on bodyweight and a favourable long-term bodyweight profile. Preliminary studies indicate that there is a high level of patient acceptability and satisfaction with quetiapine. In conclusion, quetiapine has shown efficacy against both positive and negative symptoms of schizophrenia, and has benefits in improving cognitive deficits, affective symptoms and aggression/hostility. The beneficial effects of quetiapine have been maintained for at least 52 weeks. Quetiapine was effective and well tolerated in hard-to-treat patients, and may be of particular use in these individuals. It is at least as effective as standard antipsychotics and appears to have similar efficacy to risperidone and olanzapine. The relative risk/benefit profile of quetiapine compared with other atypical antipsychotics requires further research in head-to-head trials, although quetiapine's relatively benign tolerability profile distinguishes it from other commonly used atypical agents, particularly with respect to bodyweight, EPS and plasma prolactin levels. Overall, quetiapine has an excellent risk/benefit profile and is a suitable first-line option for the treatment of schizophrenia.