Overdoses and ingestions of second-generation antipsychotics in children and adolescents

Clozapine Toxicity in Two Young Siblings Due to a Pharmacy Dispensing Error: a Pediatric Case Report

INTRODUCTION

Clozapine is an atypical antipsychotic used to treat refractory schizophrenia; in both therapeutic use and overdose, it can cause significant toxicity. We report two young siblings who developed altered mental status after ingesting clozapine due to a pharmacy dispensing error.

CASE REPORT

A 5-year-old girl and her 19-month-old sister presented to the emergency department (ED) with altered mental status after they took their first dose of what was believed to be cimetidine, prescribed to treat molluscum contagiosum. Both children were discharged after a brief period of observation in the ED. Two days later, when the older child continued to be symptomatic, their mother used a web-based pill identifier and discovered that the pills dispensed by the pharmacy were 200 mg clozapine tablets, not the cimetidine that had been prescribed. Ingestion was confirmed with an elevated serum clozapine concentration in the older child of 17 mcg/L at 85 hours post-ingestion (adult therapeutic range: 350-600 mcg/L). Both children had complete resolution of their symptoms 4 days following the ingestion with supportive care alone.

DISCUSSION

We report two cases of pediatric clozapine toxicity due to a pharmacy dispensing error. The error was due, in part, to similarly named medications being stored adjacent to each other on a shelf. Dispensing errors are not rare occurrences and their root causes are multi-factorial. This case demonstrates the importance of reducing such errors, particularly for medications with potential for severe toxicity.

Risperidone medication errors in children: an analysis of French poison centres data

OBJECTIVES

To describe clinical consequences of risperidone medication errors in children of less than 13 years and to estimate a clinically relevant toxic dose.

METHODS

All cases of risperidone medication errors managed by French Poison Centres from 2001 to 2012 were analyzed. Inclusion criteria were a delay of at least 2 hours between ingestion and request to the FPC in asymptomatic children, an ingested dose above two-fold the maximal daily dose for children above 5 years or any symptomatic patient at the time of first contact.

RESULTS

One hundred and sixty cases met our criteria. Median age was 8 years (range 0.9-12) and 28.1% were aged 5 years or less. Causes of the error were an incorrect dose in treated children (84.2%) or a dose given to a wrong child (15.8%). The median ingested dose was 0.1 mg/kg or 3.3-fold the maximum recommended dose. Overall, 59 children had no symptoms, 95 experienced minor symptoms and six moderate symptoms. Somnolence/sedation was the most common (73.3%). Of the 17 children who developed extrapyramidal disorders, all had minor or moderate symptoms and only five required a symptomatic treatment.

CONCLUSIONS

Risperidone medication errors in children cause minimal effects. Somnolence and mild to moderate extrapyramidal reactions were the main features of toxicity, and significant cardiac or other neurological features were not observed. No case with severe toxicity was noted. At home surveillance can be proposed for children exposed to a dose ≤0.15 mg/kg.

The antipsychotic story: changes in prescriptions and overdose without better safety

AIMS

Morbidity and mortality from drug overdose has decreased over three decades. This is credited to safer drugs and therefore better outcomes in overdose. We aimed to investigate changing prescriptions of antipsychotic medications and associated changes in antipsychotic overdoses over a 26-year period.

METHODS

All antipsychotic poisoning presentations to a tertiary referral toxicology unit between 1987 and 2012 were reviewed. Data were collected prospectively on demographics, ingestion information, clinical effects, complications and treatment. Rates of antipsychotic drug use in Australia were obtained from Australian government publications for 1990-2011 and linked to overdose admissions by postcode.

RESULTS

There were 3180 antipsychotic overdoses: 1235 first generation antipsychotics, 1695 'atypical' second generation antipsychotics and 250 lithium overdoses. Over 26 years, antipsychotic overdoses increased 1.8-fold, with first generation antipsychotics decreasing to one-fifth of their peak (≈80/year to 16) and second generation antipsychotics increasing to double this (≈160/year), olanzapine and quetiapine accounting for 78%. All antipsychotic overdoses had a median length of stay of 18.6 h, 15.7% admitted to intensive care unit, 10.4% ventilated and 0.13% died in hospital, which was the same for first generation compared to second generation antipsychotics. There was a 2.3-fold increase in antipsychotic prescriptions over the same period; first generation antipsychotics declined whereas there was a dramatic rise in second generation antipsychotics, mainly olanzapine, quetiapine and risperidone (79%).

CONCLUSION

Over 26 years there was an increase in antipsychotic prescribing associated with an increase in antipsychotic overdoses. Although the type of antipsychotics changed, the morbidity and mortality remained the same, so that antipsychotics are an increasing proportion of overdose admissions.

Prolonged Antimuscarinic Delirium in a Child Due to Benztropine Exposure Treated With Multiple Doses of Physostigmine

An 11-year-old boy presented with an antimuscarinic toxidrome due to benztropine and risperidone ingestion. His delirium was prolonged and difficult to treat with benzodiazepines. Multiple doses of physostigmine successfully treated it. Benztropine is a potent antimuscarinic agent, whereas risperidone has not been reported to cause antimuscarinic toxicity. The use of physostigmine to treat benztropine intoxication in a pediatric patient has not previously been described. In this case, multiple doses were used and were well tolerated.

Atypical antipsychotic poisoning in young children: a multicentre analysis of poisons centres data

Although paediatric patients frequently suffer from intoxications with atypical antipsychotics, the number of studies in young children, which have assessed the effects of acute exposure to this class of drugs, is very limited. The aim of this study was to achieve a better characterization of the acute toxicity profile in young children of the atypical antipsychotics clozapine, olanzapine, quetiapine, and risperidone. We performed a multicentre retrospective analysis of cases with atypical antipsychotics intoxication in children younger than 6 years, reported by physicians to German, Austrian, and Swiss Poisons Centres for the 9-year period between January 1, 2001 and December 31, 2009. One hundred and six cases (31 clozapine, 29 olanzapine, 12 quetiapine, and 34 risperidone) were available for analysis. Forty-seven of the children showed minor, 28 moderate, and 2 severe symptoms. Twenty-nine cases were asymptomatic. No fatalities were recorded. Symptoms predominantly involved the central nervous and cardiovascular systems. Minor reduction in vigilance (Glasgow Coma Scale score >9) (62 %) was the most frequently reported symptom, followed by miosis (12 %) and mild tachycardia (10 %). Extrapyramidal motor symptoms were observed in one case (1 %) after ingestion of risperidone. In most cases, surveillance and supportive care were sufficient to achieve a good outcome, and all children made full recovery.

CONCLUSIONS

Paediatric antipsychotic exposure can result in significant poisoning; however, in most cases only minor or moderate symptoms occurred and were followed by complete recovery. Symptomatic patients should be monitored for central nervous system depression and an electrocardiogram should be obtained.

Olanzapine: a 5-year perspective

Olanzapine is a novel antipsychotic, approved for the acute and maintenance treatment of schizophrenia and bipolar I disorder. Despite the publicity regarding reported adverse events with the novel antipsychotics, such as weight gain and Type II diabetes mellitus, olanzapine remains a useful and important medicine. It is a selective monoaminergic antagonist with high-affinity binding to a number of receptors thought to be implicated in some psychotic and mood symptoms. The complex pharmacology of olanzapine has lead to studies exploring its use in treating substance abuse, aggression/violence, borderline personality disorder, schizotypal personality disorder, obsessive-compulsive disorder and as a neuroprotective agent in schizophrenia. As the pharmacology of olanzapine and other novel antipsychotics becomes better understood, future effective treatment strategies are likely to match an individual's genetic makeup and receptor profiles to the most compatible agent.

Metabolic and toxicological considerations for obsessive-compulsive disorder drug therapy

INTRODUCTION

Obsessive-compulsive disorder (OCD) affects the daily life of the patients. Chronic nature of this disease and the need for long-term high-dose drug therapy for its maintenance increase the risk of metabolic and toxicological complications.

AREAS COVERED

In this concise article, the metabolic and toxicological aspects of major medication categories prescribed in OCD, such as serotonin-specific reuptake inhibitors, tricyclic antidepressant (clomipramine), serotonin-norepinephrine reuptake inhibitors, and atypical antipsychotics indicated in OCD (both Food and Drug Administration-approved and off-label) are discussed.

EXPERT OPINION

The most critical point in pharmacotherapy of OCD is the need for the high-dose and long-term use of drugs. In OCD, generally the higher doses of applicable drugs than those used in depression are required, often exceeding the recommended maximum dose. Moreover, such high doses should be given for at least 10 - 12 weeks to ensure the adequate treatment duration for the clinical effects to emerge. This long-term high-dose maintenance therapy increases the risk of drug toxicity and adverse effects. Physicians should take extra care in periodical assessment of signs and symptoms of metabolic and toxicological complications in patients. Subjective symptoms reported by patients should be carefully assessed and not attributed to obsessive nature of the patients.

Accidental clozapine intoxication in a toddler: clinical and pharmacokinetic lessons learnt

WHAT IS KNOWN AND OBJECTIVE

Clozapine, a second generation antipsychotic which is relatively safe in overdose, has been used as an effective treatment alternative to traditional antipsychotics. The therapeutic use in children remains controversial. However, in accordance with the increasing prescription in adults, the accidental ingestion in childhood becomes more frequent. We report the youngest case of accidental clozapine ingestion.

CASE SUMMARY

A 13-month-old girl presented with acute respiratory insufficiency and coma of unknown origin. The medical history, laboratory and radiological assessment did not link to aetiology until an almost spontaneous arousal after 22 h pointed towards intoxication. The initial standard drug screening using immunoassay had been negative. Hence, liquid chromatography mass spectrometry/mass spectrometry (LC-MS/MS) was performed, and clozapine was detected with a serum concentration of 736 ng/mL.

WHAT IS NEW AND CONCLUSION

This case illustrates the diagnostic and forensic pitfalls in a coma of unknown origin due to the limits of toxicological screening immunoassays. LC-MS/MS analysis by an established method showed clozapine metabolites (norclozapine and clozapine-N-oxide) are detectable for longer period, especially in urine, when compared with clozapine. The clinical course is presented in unique correlation with plasma and urine concentrations of clozapine and its metabolites. The elimination pattern of clozapine in toddlers is similar to adults, and the toxic dose was found to be lower when compared with school-age children and adults.

Atypical antipsychotics: trends in analysis and sample preparation of various biological samples

Atypical antipsychotics are increasingly popular and increasingly prescribed. In some countries, they can even be obtained over-the-counter, without a prescription, making their abuse quite easy. Although atypical antipsychotics are thought to be safer than typical antipsychotics, they still have severe side effects. Intoxications are not rare and some of them have a fatal outcome. Drug interactions involving atypical antipsychotics complicate patient management in clinical settings and the determination of the cause of death in fatalities. In view of the above, analytical strategies that can efficiently isolate atypical antipsychotics from a variety of biological samples and quantify them accurately, sensitively and reliably, are of utmost importance both for the clinical, as well as for the forensic toxicologist. In this review, we will present and discuss novel analytical strategies that have been developed from 2004 to the present day for the determination of atypical antipsychotics in various biological samples.

Pharmacologic management of acutely agitated pediatric patients

Acute agitation is a state of behavioral dyscontrol that requires intervention. Medications available in rapid delivery formats are frequently administered to treat acute agitation, either as a chemical restraint or on a voluntary basis. Prior to initiating treatment, the etiology of agitation must be evaluated. In choosing a medication, general pharmacologic principles should be followed. Medication should be selected based on the underlying cause in conjunction with weighing the risks, benefits, and side effects of medications. There are three classes of medications administered to children and adolescents to treat agitation: antihistamines, benzodiazepines, and antipsychotics. The most concerning short-term side effects of antipsychotics are their adverse neurologic effects, neuroleptic malignant syndrome, and prolonged corrected QT interval. Compared with typical antipsychotics, atypical antipsychotics have a more favorable short-term side effect profile.

Olanzapine approved for the acute treatment of schizophrenia or manic/mixed episodes associated with bipolar I disorder in adolescent patients

BACKGROUND

Severe and persistent mental illnesses in children and adolescents, such as early- onset schizophrenia spectrum (EOSS) disorders and pediatric bipolar disorder (pedBP), are increasingly recognized. Few treatments have demonstrated efficacy in rigorous clinical trials. Enduring response to current medications appears limited. Recently, olanzapine was approved for the treatment of adolescents with schizophrenia or acute manic/mixed episodes in pedBP.

METHODS

PubMed searches were conducted for olanzapine combined with pharmacology, schizophrenia, or bipolar disorder. Searches related to schizophrenia and bipolar disorder were limited to children and adolescents. The bibliographies of the retrieved articles were hand-checked for additional relevant studies. The epidemiology, phenomenology, and treatment of EOSS and pedBP, and olanzapine's pharmacology are reviewed. Studies of olanzapine treatment in youth with EOSS and pedBP are examined.

RESULTS

Olanzapine is efficacious for EOSS and pedBP. However, olanzapine is not more efficacious than risperidone, molindone, or haloperidol in EOSS and is less efficacious than clozapine in treatment-resistant EOSS. No comparative trials have been done in pedBP. Olanzapine is associated with weight gain, dyslipidemia, and transaminase elevations in youth. Extrapyramidal symptoms, neuroleptic malignant syndrome, and blood dyscrasias have also been reported but appear rare.

CONCLUSIONS

The authors conclude that olanzapine should be considered a second-line agent in EOSS and pedBP due to its risks for significant weight gain and lipid dysregulation. Awareness of the consistent weight and metabolic changes observed in olanzapine-treated youth focused attention on the potential long-term risks of atypical antipsychotics in youth.

Increased aripiprazole concentrations in an HIV-positive male concurrently taking duloxetine, darunavir, and ritonavir

OBJECTIVE

To report a case of increased aripiprazole concentrations during coadministration with darunavir, ritonavir, and duloxetine.

CASE SUMMARY

A 43-year-old HIV-positive Hispanic man received darunavir/ritonavir-based antiretroviral therapy (ART) in addition to aripiprazole and duloxetine for depression and anxiety. A month after the aripiprazole dosage was increased to 50 mg daily, the patient developed confusion and loss of coordination. Weeks later, he presented to the emergency department with fever, cough, headache, neck stiffness, back pain, and blurred vision and was admitted for possible meningitis. Because symptoms improved with pain control and intravenous fluids during hospitalization, he was discharged within a couple days after admission. One month later he was readmitted for worsening symptoms, and the resulting diagnostic workup showed unremarkable findings except for lymphadenopathy (LAD). This finding was attributed to discontinuing ARTs after his first admission. He was discharged on aripiprazole 50 mg daily, darunavir 800 mg daily, ritonavir 100 mg daily, and duloxetine 60 mg daily. A random steady-state concentration of aripiprazole was 1100 ng/mL (therapeutic concentration 100-200 ng/mL) obtained 49 days after discharge.

DISCUSSION

The Horn Drug Interaction Probability Scale demonstrated a possible relationship between the increased aripiprazole concentration and coadministration of darunavir/ritonavir and duloxetine, which inhibit CYP3A4 and 2D6. Potential confounders to the increased concentration include duloxetine inhibition of CYP2D6 polymorphism, possible 2D6 polymorphism, and exceeding aripiprazole's maximum dose. The initial presentation of confusion and loss of coordination may have been early signs of aripiprazole toxicity, which relapsed as shown by his symptoms prior to admission.

CONCLUSIONS

The interaction between aripiprazole and darunavir, ritonavir, and duloxetine may be significant. Clinicians should be cognizant of increased risk of aripiprazole toxicity in HIV-positive patients concurrently taking ritonavir-boosted ART and other cytochrome P450 inhibitors like duloxetine. Dose adjustments or monitoring parameters should be an area of research and discussion.

Prolonged delirium after quetiapine overdose

Quetiapine is an atypical antipsychotic agent increasingly used to treat schizophrenia and bipolar disorder in pediatric patients. Few published data exist concerning quetiapine's effects in therapeutic settings or short-term overdose in pediatric and adolescent populations. In this report, we describe a 15-year-old adolescent girl who experienced continued delirium 5 days after an overdose of quetiapine, trazodone, and clonidine. The patient initially presented with sedation and stable vital signs. After 3 days of gradual improvement, she experienced episodes of delirium coinciding with an increase in resting heart rate. On the basis of suspicion for quetiapine-associated antimuscarinic effects, the patient was administered intravenously with physostigmine on the fifth day after ingestion. Treatment resulted in a brief resolution of symptoms. Serum quetiapine levels measured 1 day and 5 days after ingestion were 3400 and 4800 ng/mL, respectively. The use of physostigmine and interpretation of serum levels are discussed further.

Respiratory failure following isolated ziprasidone ingestion in a toddler

Ziprasidone is an atypical antipsychotic approved for the treatment of schizophrenia and bipolar mania in adults and is used off label in children and adolescents. Despite increasing use of ziprasidone in both adult and pediatric populations, there remains a paucity of reports describing unintentional pediatric exposures. The following report describes a patient with isolated ziprasidone ingestion who required intubation secondary to respiratory failure. A 15-month-old previously healthy boy presented to the emergency department shortly after his father found him with approximately five partially dissolved 80-mg ziprasidone tablets in his mouth. The child was flaccid and lethargic with no eye opening, withdrawing from pain only. Two hours after arrival, he developed worsening CNS depression with inability to protect his airway and underwent endotracheal intubation. A serum ziprasidone level was 330 ng/mL by LC/MS. The patient was extubated approximately 14 h later and was discharged from the hospital shortly thereafter in good health without neurological sequelae. Isolated pediatric ingestion of ziprasidone resulting in the need for significant medical intervention has not been previously reported. We report a case of respiratory failure requiring intubation following accidental ziprasidone ingestion with confirmatory serum levels.

D2 antagonist during development decreases anxiety and infanticidal behavior in adult female prairie voles (Microtus ochrogaster)

On postnatal day 8, prairie vole pups were randomly assigned a treatment of 1mg/kg SKF38393 (D1 agonist), quinpirole (D2 agonist), SCH23390 (D1 antagonist), eticlopride (D2 antagonist), or saline vehicle. As adults, females treated with eticlopride exhibited reduced anxiety-like behavior in an elevated plus maze and a reduction in infanticidal behavior. These behavioral effects were not seen in males. These data demonstrate that a single exposure to a D2 antagonist during development can have persistent, sex-specific effects on behavior into adulthood.

An unreported side effect of risperidone in children: sinus arrest with long pauses causing syncope

Risperidone has been reported as a well-tolerated antipsychotic in children. The most common side effects of risperidone are anxiety, headaches, insomnia, and agitation, which frequently appear with high doses. Although it is known that risperidone affects the cardiac conduction system, symptomatic bradycardia has not been reported previously in children. We report a child who developed syncope because of sinus arrest with long pauses (>3 seconds) with therapeutic doses of risperidone. This case suggests that close monitoring is mandatory even during therapeutic treatment with risperidone.

Pediatric ziprasidone overdose

We describe the first ziprasidone overdose with quantitative serum levels of a pediatric patient in coma and with pinpoint pupils. This case is an important contribution to the pediatric ziprasidone literature because it illustrates that ingestion of just 1 pill may result to profound mental status and respiratory depression in a child. H.C., a 30-month-old girl, presented to the emergency department approximately 30 minutes after an accidental ingestion of an adult family member's medication. The child was found on the floor surrounded by numerous pills and was witnessed to have ingested at least 1 tablet by a caregiver. After finding the child with the pills, the family observed the child for a brief period but transported her to the hospital after she became lethargic and unresponsive. The child received 2 doses of 0.4 mg of intravenous naloxone without change in her neurologic status. The child then underwent a rapid sequence intubation for airway protection and subsequently received gastrointestinal decontamination with 15 g of activated charcoal via the orogastric tube. Ziprasidone is an atypical antipsychotic drug that was approved by the Food and Drug Administration in February 2001 for the general treatment of schizophrenia in adults. Previously reported pediatric ziprasidone overdoses describe a syndrome of sedation, tachycardia, hypotonia, and coma consistent with that of the patient described in this paper. In pediatric ziprasidone overdose, QTc prolongation and hypotension have also been illustrated, but seizures have not been reported. An interesting aspect of this case is the development of pinpoint pupils unresponsive to naloxone. This phenomenon has been reported before with overdose of olanzapine, a similar atypical antipsychotic. The mechanism of miosis associated with overdose of atypical antipsychotics is unclear but is likely related to interference with central innervation of the pupil. Pupil size is maintained by a balance between sympathetic and parasympathetic neurohumeral tones. We propose that an overdose of an alpha-1 receptor blocking agent, such as ziprasidone, results in unopposed parasympathetic stimulation resulting in miosis.

Focus on ziprasidone: a review of its use in child and adolescent psychiatry

OBJECTIVE

To review published literature regarding ziprasidone in child and adolescent psychiatry.

METHODS

A literature review was conducted using the medline search term: 'ziprasidone' with limits: Human trials, English language, All Child (Age 0-18). Additional articles were identified from reference information and poster presentation data.

RESULTS

Two randomized controlled trials and five prospective open-label studies have been conducted with ziprasidone. Additionally, several case reports and case series are reviewed. Ziprasidone has a greater propensity for QT(c) prolongation and risk for fatal arrhythmias compared to other atypical antipsychotics. Careful history taking regarding presence of congenital long QT syndrome is essential. Given limited clinical experience, electrocardiogram monitoring at baseline and following attainment of ziprasidone target dosage is warranted. No deaths from overdose have been reported in children and adolescents. Ziprasidone has a low potential for extrapyramidal side effects. Prolactin changes are small and transient. Lethargy, drowsiness, agitation and tachycardia were the most common adverse effects in randomized trials. Body weight changes with ziprasidone were comparable to placebo-treated subjects.

CONCLUSION

At present, ziprasidone should be considered a second or third-line option for a limited set of conditions. A role may exist for ziprasidone in patients who have experienced significant metabolic adverse effects with other atypical antipsychotics.