Acute Quetiapine Overdose in Adults: A 5-Year Retrospective Case Series

Biodetoxification Using Intravenous Lipid Emulsion, a Rescue Therapy in Life-Threatening Quetiapine and Venlafaxine Poisoning: A Case Report

The administration of intravenous lipid emulsion (ILE) is a proven antidote used to reverse local anesthetic-related systemic toxicity. Although the capacity of ILE to generate blood tissue partitioning of lipophilic drugs has been previously demonstrated, a clear recommendation for its use as an antidote for other lipophilic drugs is still under debate. Venlafaxine (an antidepressant acting as a serotonin-norepinephrine reuptake inhibitor (SNRI)) and quetiapine (a second-generation atypical antipsychotic) are widely used in the treatment of psychotic disorders. Both are lipophilic drugs known to induce cardiotoxicity and central nervous depression. We report the case of a 33-year-old man with a medical history of schizoaffective disorder who was admitted to the emergency department (ED) after having been found unconscious due to a voluntary ingestion of 12 g of quetiapine and 4.5 g of venlafaxine. Initial assessment revealed a cardiorespiratory stable patient but unresponsive with a GCS of 4 (M2 E1 V1). In the ED, he was intubated, and gastric lavage was performed. Immediately after the admission to the intensive care unit (ICU), his condition quickly deteriorated, developing cardiovascular collapse refractory to crystalloids and vasopressor infusion. Junctional bradycardia occurred, followed by spontaneous conversion to sinus rhythm. Subsequently, frequent ventricular extrasystoles, as well as patterns of bigeminy, trigeminy, and even episodes of non-sustained ventricular tachycardia, occurred. Additionally, generalized tonic-clonic seizures were observed. Alongside supportive therapy, antiarrhythmic and anticonvulsant therapy, intravenous lipid emulsion bolus, and continuous infusion were administered. His condition progressively improved over the following hours, and 24 h later, he was tapered off the vasopressor. On day 2, the patient repeated the cardiovascular collapse and a second dose of ILE was administered. Over the next few days, the patient's clinical condition improved, and he was successfully weaned off ventilator and vasopressor support. ILE has the potential to become a form of rescue therapy in cases of severe lipophilic drug poisoning and should be considered a viable treatment for severe cardiovascular instability that is refractory to supportive therapy.

Combined effects of methadone and quetiapine on respiratory rate, haemodynamic variables, and temperature in conscious rats

Fatal poisonings where both methadone and quetiapine are detected post-mortem occurs frequently in legal autopsy cases. It is unclear whether quetiapine increases the risk of fatal methadone poisoning or if it is merely detected due to widespread use. We hypothesized that methadone and quetiapine would have additive toxic effects on respiratory rate, blood pressure, and the QTc-interval. To investigate this hypothesis, we used telemetry implants for measurements of respiratory rate, haemodynamic variables, the velocity of blood pressure changes, temperature, and movement in conscious, freely moving male Wistar rats aged 12-13 weeks. The combined effects of three accumulative i.p. doses of methadone (2.5, 10, 15 mg/kg) and quetiapine (3, 10, 30 mg/kg) were compared to rats treated with the same doses of each drug alone, and a vehicle-treated group in a randomized investigator blinded study. No additive effects of quetiapine and methadone on respiratory rate, haemodynamic variables, or movement were observed. However, body temperature was significantly lower by approximately 1.5°C on average in the group treated with both methadone and quetiapine (15 + 30 mg/kg) compared to the other groups. This indicates a synergistic effect of quetiapine and methadone on thermoregulation, which may increase the risk of fatal poisoning. We suggest studying this finding further in human settings.

Analysis of umbilical cord tissue as an indicator of in utero exposure to toxic adulterating substances

In utero drug exposure is a significant public health threat to the well-being and normal development of the neonate. Recently, testing of umbilical cord tissue (UCT) has been employed to measure illicit drug exposure, as drugs used by the mother during the third trimester may be retained in the UCT. Focus has also been given to potential adverse health effects among drug users, resulting from exposure to pharmacologically active adulterants and cutting agents in the street drug supply. The in utero effects of these substances have not been well studied in humans, nor has their presence been demonstrated as a means for assessing adverse health effects in the neonate. Here, we describe the application of a novel test method to analyze UCT for the presence of more than 20 common adulterating/cutting substances via LC/Q-TOF. In total, 300 de-identified UCT samples were analyzed-all had previously tested positive for cocaine or opiates. Generally, the positivity rates of individual compounds were similar between the Cocaine and Opiates Subgroups, apart from levamisole, xylazine, dipyrone (metabolites), and promethazine. Many of the adulterants used in the street drug supply do have legitimate medicinal/therapeutic uses, including several of the compounds most frequently detected in this study. Caffeine and lidocaine were the most frequently identified compounds both individually (>70% each) and in combination with each other. Alternatively, levamisole, an adulterant with no legitimate therapeutic use, was present in 12% of cases. Importantly, this data demonstrates that the detection of traditional drugs of abuse may serve as indicators of potential in utero exposure to toxic adulterating substances during gestation. While there is cause for concern with respect to any unintentional drug exposure, illicit drug use during pregnancy, including uncontrolled dosing, poly-adulterant consumption, and the interactions of these drug mixtures, produces a significant public health threat to the neonate which warrants further study.

Combined effects of quetiapine and opioids: A study of autopsy cases, drug users and sedation in rats

Fatal opioid poisonings often involve methadone or morphine. This study aimed to elucidate if quetiapine, a widely used sedative antipsychotic medication, may increase the risk of fatal opioid poisoning by additive inhibitory effects on the central nervous system. We used data from 323 cases of fatal methadone or/and morphine poisonings autopsied from 2013 to 2020, a survey of 34 drug users, and performed blinded placebo‐controlled studies in 75 Flinders Resistant Line rats receiving three cumulative intraperitoneal doses of vehicle, methadone (2.5, 10 and 15 mg/kg), morphine (3.75, 15 and 22.5 mg/kg), quetiapine (3, 10 and 30 mg/kg) or quetiapine combined with methadone or morphine. Quetiapine was detected in 20.4% of fatal opioid poisonings with a significantly increased frequency over time, primarily in low or therapeutic concentrations, and was not associated with methadone or morphine concentrations. Use of quetiapine, most commonly in low‐to‐moderate doses to obtain a sleep‐inducing or tranquillizing effect, was reported by 67.6% of survey respondents. In the animal studies, a significant impairment of sedation score, performance on the rotarod and open field mobility was observed in all treatment groups compared with vehicle. However, the effect of quetiapine plus the opioid was not significantly different from that of the opioid alone. Thus, no additive sedative effects were observed in rats. Our results suggest that quetiapine is more often an innocent bystander than a contributor to fatal opioid poisoning. However, the combined effects on other parameters, including blood pressure, cardiac rhythm and respiratory rate, need investigation.

Physostigmine should be used more readily for antimuscarinic toxicity: PRO

Physostigmine is the preferred treatment for antimuscarinic toxicity. Its use has a clear biological rationale and is supported by extensive clinical use which demonstrated effectiveness and safety.

Metabolic Acidosis in Multi Drug Poisoning with Antidepressants and Antipsychotics

Objective:

In this study, we evaluated the predictive factors for the occurrence of metabolic acidosis in patients with multi-drug poisoning, including antidepressants (Ad)/antipsychotics (Ap).

Methods:

This cross-sectional study was carried out in the referral poisoning center, Khorshid University Hospital, affiliated with Isfahan University of Medical Sciences. All patients with multi-drug ingestion, including Ad/Ap, were included in the study. Patients were divided into two groups with and without metabolic acidosis. Demographic factors, time from ingestion to admission, clinical manifestations, length of hospital stay, and outcome were compared in two groups. Binary logistic regression was used to identify factors associated with the risk of metabolic acidosis occurrence.

Findings:

Among the 206 evaluated patients, 45 patients (21.8%) had metabolic acidosis whom the majority were female (73.3%) with intentional purposes (77.8%). 31.1% of the patients with metabolic acidosis had tachycardia on admission (P = 0.03). Among all variables, time from ingestion to admission (P = 0.02) and lengths of hospital stay (P = 0.002) were significantly different between patients with and without metabolic acidosis. Tachycardia on admission (adjusted odds ratio [OR], 2.24; 95% confidence interval [CI]: 1.05–4.76; P = 0.036) and time from ingestion to admission (adjusted OR, 1.06; 95% CI: 1.00–1.13; P = 0.04) were also the predictive factors in occurrence of metabolic acidosis. Most of the patients survived without any complications (94.6%), of whom 72.3% had no previous underlying somatic diseases (P = 0.05).

Conclusion:

Admission tachycardia and the time elapsed from ingestion to admission may be considered important factors for predicting metabolic acidosis in multi-drug poisoning, including Ad/Ap.

Quetiapine and other antipsychotics combined with opioids in legal autopsy cases: A random finding or cause of fatal outcome?

Opioid poisoning is a frequent cause of death in drug addicts and occurs with opioid treatment. Quetiapine is often found in forensic autopsies and may increase the risk of fatal opioid poisoning by enhancing sedation, respiratory depression, hypotension and QT prolongation. We systematically searched for studies of acute toxicity of quetiapine or other antipsychotics combined with morphine or methadone. Case reports describing toxicity of quetiapine combined with morphine or methadone were also included. We retrieved one human study that observed pharmacokinetic interaction between quetiapine and methadone, and 16 other human studies. Fourteen investigated the combination of droperidol and morphine in treatment doses, and some indicated an additive sedative effect. Five animal studies with acepromazine in combination with morphine or methadone were located and indicated an additive effect on sedation and hypotension. Six forensic case reports in which death could have been caused solely by quetiapine, the opioid, or other drugs were found. Thus, acute toxicity of quetiapine combined with morphine or methadone has not been studied. Because of quetiapine's effects on alpha-adrenoceptors, muscarinic and histamine receptors, human ether-a-go-go-channels and methadone kinetics, we suggest further research to clarify if the indicated additive effects of opioids and droperidol or acepromazine are also true for quetiapine.

The Added Value of Liquid Antipsychotics: The Case of Quetiapine

Background:

Antipsychotic drugs are the cornerstone of schizophrenia treatment and are also indicated for other psychotic and mood disorders. Different antipsychotic drugs and their formulations are available, though liquid forms have been overlooked.

Methods

Herein the added value of liquid antipsychotics is reviewed, with a focus on the recently introduced liquid quetiapine, a frequently used antipsychotic.

Results

Liquid antipsychotics are easily administrated via the preferable oral route, while compliance under supervised administration is transparent. Liquid forms could be preferred in patients with swallowing difficulties, which are common in elderly patients and often concealed. In this population, the availability of liquid antipsychotics could prevent errors in medication administration, which could possibly render caregivers labile to any harm caused to the patient. Aspiration, however, remains a risk with liquid formulations. Common errors in medication administration are the omission of treatment and alteration of solid oral formulations. Regarding quetiapine, omission of treatment could be associated with non-adherence as well as discontinuation symptoms, while alteration of extended release formulation could alter its pharmacokinetics. Mildly agitated and cooperative patients are another target population of liquid antipsychotics, which can induce fast sedation avoiding involuntary intramuscular injections. The combination of sedative properties and low incidence of extrapyramidal symptoms makes liquid quetiapine a valuable option for these patients, yet the current evidence is limited.

Conclusion

The liquid form of quetiapine can facilitate pharmacotherapy of schizophrenia and can be defined as value added medicine bringing key benefits not only to the patients and caregivers but also to the health care system.

Quetiapine Poisoning and Factors Influencing Severity

PURPOSE/BACKGROUND

Quetiapine is a relatively new atypical antipsychotic with fewer adverse effects. It is increasingly prescribed to patients. The purpose of this study was to describe the cases of poisoning observed at the western France Poison Control Centre and identify potential risk factors that increase the severity of the cases.

METHODS

This was a retrospective study of self-poisoning with quetiapine as reported by the western France Poison Control Centre between 2007 and 2017.

RESULTS

There were 372 cases of quetiapine poisoning. Circumstances are known in 367 of 372 cases. There were 75 cases of null severity (grade 0), 133 cases of mild severity (grade 1), 85 cases of moderate severity (grade 2), and 79 cases of high severity (grade 3). Five deaths were listed in this series. The most commonly observed symptoms were neurological and cardiovascular in nature (drowsiness, coma, tachycardia, hypotension). Of these cases, 79.8% included voluntary ingestions. Among 302 cases with coagents, the most common coagents were benzodiazepines (56%), other psychotropic drugs (41%), and antidepressants (37%). An evaluated ingested dose 1500 mg or greater and 2 or more coagents increase the risk of severe poisoning. In particular, concomitant ingestion of benzodiazepines and antidepressants with quetiapine was associated with high severity (odds ratio, 2.478 [confidence interval, 1.3-4.723]; odds ratio, 1.820 [confidence interval, 1.010-3.316]).

CONCLUSIONS

Quetiapine may lead to severe poisoning for which there is currently no specific treatment. Patients and practitioners should be aware of this when quetiapine is prescribed, particularly when used in combination with other medications, and in order to deal with cases of poisoning.

Restarting antidepressant and antipsychotic medication after intentional overdoses: need for evidence-based guidance

Intentional drug overdoses with antidepressant and antipsychotic medications are an increasingly common problem. Currently, there is little guidance with regard to reintroduction of these medications after intentional overdoses. We have used published toxicological and pharmacokinetic data to obtain factors which control the recovery from overdoses. From such data, we have proposed guidance regarding their reintroduction, provided there are no adverse effects or contraindications. Tentatively, we suggest that when adverse effects from the overdose are lost, treatment could recommence after a further mean half-life of elimination. Most antidepressant and antipsychotic drugs are metabolized by cytochrome P450 enzymes and, where cytochrome P450 inhibitors are co-ingested, serial plasma concentrations should optimally be obtained in order to assess a suitable time for reintroduction of the psychoactive drugs. We hope the proposals presented will stimulate research and discussion that lead to better guidance for clinicians concerning reintroduction of psychoactive medication after intentional overdose.

Extended-release quetiapine overdose is associated with delayed onset of toxicity compared to immediate-release quetiapine overdose

OBJECTIVES

There are currently no studies comparing toxicity after extended-release (XR) and immediate-release (IR) quetiapine overdose. To compare the time course of toxicity of XR and IR quetiapine overdose.

METHODS

Retrospective analysis of toxicology unit consultations from July 2013 to April 2016. Information extracted included demographics, type of ingestion (IR, XR, mixed formulation, dose, tablet count, time to presentation, sedative co-ingestants), lowest Glasgow coma score (GCS), time to lowest GCS, fastest pulse, lowest systolic blood pressure, and time to recovery from sedation.

RESULTS

There were 256 presentations in 210 patients. Females 86% (n = 181), median age 30.5 years (IQR 23-43). Median quetiapine dose for the whole cohort was 2 g (IQR 1-5). Sedating co-ingestants were seen in 61% of presentations. Comparison of IR (n = 43) and XR quetiapine (n = 23) ingestions without sedating co-ingestants revealed a larger median ingested dose for XR formulation: 5.7 g versus 1.75 g (P = 0.004) and larger median tablet strength (XR 200 mg vs IR 100 mg, P < 0.001). Median time to lowest GCS: XR 7 h (IQR 4.9-11) versus IR 3.8 h (IQR 2.4-5.7), P < 0.001. Median time to peak pulse: XR 9 h (IQR 3-12) versus IR 2.5 h (IQR 1.5-5), P = 0.01. Median time to recovery from sedation: XR quetiapine 20 h (IQR 12-39) versus 12 h (IQR 5.5-22), P < 0.05. Median duration of intubation: XR 47 h versus 17 h for IR, P = 0.04).

CONCLUSION

XR quetiapine overdoses without sedating co-ingestants were associated with a doubling of time to peak sedation and pulse, and had longer recovery from sedation. The absence of sedation or tachycardia 12 h post-overdose of XR quetiapine seems a reasonable timeframe to rule out significant poisoning.

What are the Predictive Factors for the Treatment Outcomes in Multi Drug Poisoning Including Antidepressants/Antipsychotic Drugs?

Background

There have been studies on the outcome of acute intoxication with antidepressants or antipsychotics. We performed outcome prediction analysis in acute poisoning patients with antidepressants/antipsychotics with or without combination with other drugs.

Materials and Methods

A cross-sectional study was performed in Khorshid (PBUH) University Hospital affiliated with Isfahan University of Medical Sciences from March 2016 to May 2017. Patients with acute poisoning ingested antidepressants and antipsychotics with or without other drugs were included in the study. The outcome was categorized as survived without complications and complications/death. Binary regression analysis was performed for outcome prediction.

Results

The data from 239 patients were analyzed. Most of the patients were female (68.2%), 5.9% of patients admitted to the Intensive Care Unit. About 94.99% of patients survived without complications. There was a significant difference between patients with and without complications with respect to the level of consciousness, hypotension, seizure, electrocardiography findings, pulse rate after 24 hours (h) of admission, and need to endotracheal intubation (P < 0.0001). Binary logistic regression analysis showed admission level of consciousness (stupor/coma) (odds ratio [OR] =8.07; P = 0,005), hypotension (OR = 12.16; P = 0.001), seizure (OR = 11.15; P = 0.009), tachycardia after 24 h of admission (OR = 22.50; P = 0.003), and need for endotracheal intubation (OR = 10.47; P = 0.002) were determinant factors in outcome prediction.

Conclusions

Stupor/coma and hypotension were the predictive factors for outcome. Patients with seizure and tachycardia after 24 h of admission; and those intubated and received mechanical ventilation had a higher chance of complications.

Cardiovascular Safety of Psychiatric Agents: A Cautionary Tale

Psychiatric agents are among the most commonly prescribed medications. Despite the advent of newer generation agents, patients receiving them still experience cardiovascular (CV) side effects. However, these agents may have heterogeneous properties, calling for an individualized approach based on efficacy and also on the particular side effect profile of each specific agent. Proarrhythmic effects arising from drug-induced long-QT syndrome and consequent potentially life-threatening polymorphic ventricular arrhythmias in the form of torsade de pointes, the metabolic syndrome contributing to atherosclerosis and acute coronary syndromes, and drug-induced orthostatic hypotension raise major concerns. Of course, it is also crucial that fear of potential CV adverse effects does not deprive psychiatric patients of appropriate drug therapy. Modification of CV risk factors in psychiatric patients together with optimal management of their CV diseases and appropriate selection of psychotropic agents with greater efficacy and least CV toxicity are of paramount importance in mitigating CV risks and enhancing safety. Identifying patients at high risk of CV complications and close monitoring of all patients receiving these agents are crucial steps to prevent and manage such complications. All these issues are herein reviewed, relevant guidelines are discussed, and schemas are depicted that illustrate the interrelated connections among the psychotropic agents and their CV effects.

Increasing rates of quetiapine overdose, misuse, and mortality in Victoria, Australia

BACKGROUND

Quetiapine is misused due to its anxiolytic and hedonic effects and has been associated with deliberate self-harm. This study analyzed quetiapine-related calls to the Victorian Poisons Information Centre (VPIC), coronial data from Victorian Institute of Forensic Medicine (VIFM) and prescribed data from the Pharmaceutical Benefits Scheme (PBS) to determine current trends in overdose, misuse and mortality.

METHODS

This was a retrospective review of multiple databases. Calls to VPIC and coronial data from the VIFM were reviewed from 2006 to 2016. PBS prescription data from 2000 to 2015 was obtained from the Australian Statistics on Medicines website.

RESULTS

VPIC data indicated a 6-fold increase in the number of quetiapine-related calls over the 11-year period of which most were overdose-related (77%). Overdose and misuse calls increased by 6-fold and 6.6-fold, respectively. Coronial data also indicated a rise in quetiapine-related harm; a 7.4-fold increase in quetiapine-related deaths was recorded for the same period. Similarly, Australian PBS data showed that quetiapine prescriptions increased 285-fold since 2000. There was a significant positive correlation between the increase in prescribing and overdose (r = 0.75, p < 0.001), and prescribing and mortality (r = 0.82, p < 0.01).

CONCLUSIONS

This study revealed an increasing trend of misuse, non-fatal and fatal overdoses in Victoria over the last decade. The increasing rates of prescriptions in Australia and thus increased quetiapine availability are likely to have contributed to increased poisoning and mortality. Further research is warranted to explore the reasons behind increased prescribing, including off-label use.

Delayed-Onset Seizure in a Mild Quetiapine Overdose: Report of a Case and Review of the Literature

Among atypical antipsychotics, quetiapine is commonly prescribed and considered to have a favorable side effect and safety profile. Here, we report the case of a patient who developed a generalized tonic-clonic seizure 28 hours following ingestion of 1,400 mg of quetiapine. Review of the literature identifies delayed-onset seizure as a potential complication of quetiapine overdose. Unique to this case, delayed-onset seizures occurred in a patient with a relatively low dose of quetiapine and no obvious toxidrome, suggesting that this reaction may be an important consideration in the management of quetiapine overdose. The pharmacokinetics and pharmacodynamics of quetiapine may explain this unusual phenomenon.

"I love having benzos after my coke shot": The use of psychotropic medication among cocaine users in downtown Montreal

BACKGROUND

Cocaine abuse is a major public health issue due to its role in the HIV and hepatitis C virus (HCV) epidemics in North America. A significant area of concern among people who use cocaine (PWUC), injected or smoked, is their frequent misuse of prescription drugs, particularly psychotropic medication (PM), such as tranquilizers, sedatives, stimulants, and antipsychotics. This paper aims to describe and understand practices of PM use among PWUC in downtown Montreal.

METHOD

Ethnographic methods including participant observation and semi-structured interviews were used in an iterative manner.

RESULTS

Two thirds of the 50 participants were male. They ranged in age from 20 to 60 and most were homeless. A significant proportion of them reported polydrug use patterns that included frequent concomitant opioid use (heroin and/or prescription opioids (PO)). Benzodiazepine-based tranquilizers and the atypical antipsychotic quetiapine were the most frequently used PM. Routes of PM administration were oral, nasal and, to a lesser degree, intravenous. Five main PM use practices were identified: 1) "downers" from cocaine high (benzodiazepines and quetiapine); 2) enhancers of heroin/PO effects (benzodiazepines); 3) reducers or suppressors of heroin/PO withdrawal symptoms (benzodiazepines); 4) enablers of a different type of "trip" (benzodiazepines); and 5) treatment for mental and physical problems (benzodiazepines and quetiapine).

CONCLUSION

PM use practices showed several complementary functions that PM fulfill in a context of polydrug use. The soothing and stimulating effects of PM reinforce the patterns of drug use among participants, posing various risks including overdose, HIV/HCV transmission, PM dependence and accidents. The results highlight the need for clinicians to assess clients' substance use patterns when prescribing PM and to question PWUC about PM use. The findings also underline certain unmet service needs in relation to overdose, HIV/HCV and mental health prevention/treatment among cocaine users.

Low-dose intravenous lipid emulsion for the treatment of severe quetiapine and citalopram poisoning

The treatment of quetiapine and/or citalopram poisoning is mainly supportive and involves gastric lavage, activated charcoal, intubation, and mechanical ventilation. Recently, however, there were reports of successful treatment with intravenous lipid emulsion. Here we report a case of a 19-year-old Caucasian girl who ingested approximately 6000 mg of quetiapine, 400 mg of citalopram, and 45 mg of bromazepam in a suicide attempt. The patient developed ventricular tachycardia and epileptic seizures 12 h after admission to the hospital. As the patient's condition deteriorated, we combined standard therapy (intubation, mechanical ventilation, and vasopressors) with low-dose intravenous lipid emulsion (ILE) (a total of 300 mL of 20 % lipid emulsion) and normalised her heart rhythm and stopped the seizures. She was discharged to the psychiatric ward after 48 h and home after a prolonged (2-month) psychiatric rehabilitation. Intravenous lipid emulsion turned out to be effective even in the lower dose range than previously reported for quetiapine poisoning in patients presenting with seizure and ventricular arrhythmia. To our knowledge, there are no case reports describing the use of ILE in treating citalopram poisoning.

Convulsive syncope related to a small dose of quetiapine in an adolescent with bipolar disorder

Quetiapine, an atypical antipsychotic, has been extensively used in patients with bipolar disorder. Overdose of quetiapine can result in severe complications, such as coma, seizure, respiratory depression, arrhythmia, and even death. However, the paucity of toxicological evaluation in adolescence causes more potential risks in this population. Herein, we present a case of hypotension and convulsive syncope after exposure to a small dose of quetiapine in a 16-year-old who was diagnosed with bipolar disorder. After cessation of quetiapine, no additional convulsive movements were reported. This case indicates that even in young patients without predisposing factors, close monitoring of adverse effects should be warranted for safety concerns, especially at the initiation of quetiapine treatment.

Intentional Recreational Abuse of Quetiapine Compared to Other Second-generation Antipsychotics

INTRODUCTION

Case reports and poison center data have demonstrated that the second-generation antipsychotic quetiapine is being obtained and used for recreational abuse. The purpose of this study was to describe the relative rates of single-substance abuse for different atypical antipsychotics and compare their demographic and clinical features.

METHODS

We conducted a 10-year retrospective analysis of the National Poison Data System (NPDS) database (2003 - 2013). Trained nurses and pharmacists with specialty training in toxicology prospectively collect all NPDS data at poison control centers around the United States. We queried the NPDS for all cases of single-substance second-generation antipsychotic exposures coded as "intentional abuse." The data provided by the NPDS regarding rates and clinical features of quetiapine abuse and the abuse of all other second-generation antipsychotics were compared and described descriptively.

RESULTS

During the study period, 2,118 cases of quetiapine abuse and 1,379 cases of other second-generation antipsychotic abuse were identified. Quetiapine abuse was more common than the abuse of other second-generation antipsychotics, compromising 60.6% of all abuse cases during the study period. After quetiapine, the next most frequently abused medications were risperidone (530 cases, 15.2%) and olanzapine (246 cases, 7.0%). For all second-generation antipsychotics including quetiapine, central nervous system clinical effects were most common, including drowsiness, confusion, and agitation. Other serious clinical effects observed with second-generation antipsychotic abuse included hypotension, respiratory depression, and seizures.

CONCLUSION

Quetiapine abuse is relatively common, and is abused far more often than any other second-generation antipsychotic. Emergency physicians should be aware of the clinical effects that may occur after second-generation antipsychotic abuse.

Comparison of pediatric atypical antipsychotic exposures reported to U.S. poison centers

CONTEXT

The rise in atypical antipsychotic prescribing increases the risk of pediatric exposures. Published studies in children are limited.

OBJECTIVE

The objectives are to evaluate national poison center data on atypical antipsychotic exposures in young children and compare toxicity amongst selected agents.

MATERIALS AND METHODS

A retrospective study of U.S. National Poison Data System single substance exposures, from 2005 to 2013, of five atypical antipsychotics in children <6 years old, followed to known outcome was performed. Data were evaluated for reason, clinical effects, management site and outcome.

RESULTS

There were 16,935 exposures included: 5018 aripiprazole, 1735 olanzapine, 3904 quetiapine, 4778 risperidone and 1500 ziprasidone. Median age was two years. Most common reason was unintentional-general (90.6%). Therapeutic error occurred more often with risperidone (19.9%). Clinical effects occurred in 59.4% of aripiprazole, 57.9% of olanzapine, 56.6% of ziprasidone, 40.1% of risperidone, and 29.3% of quetiapine. The most frequent were drowsiness/lethargy (35.6%), tachycardia (6.9%), agitation (4.0%), and ataxia (3.3%). Drowsiness/lethargy occurred most with aripiprazole (47.6%), ziprasidone (46.5%) and olanzapine (45.1%) and least with quetiapine (20.5%) and risperidone (28.6%). Tachycardia and agitation both occurred most often with olanzapine (11.4% and 12.7%, respectively). Management sites were non-health care facility (28.0%), treated/discharged from emergency department (48.9%), admitted - noncritical care (11.4%), critical care (9.5%), and other/unknown (2.2%). Admission was lowest for risperidone (13.9%) and quetiapine (11.9%) and highest for olanzapine (32.9%). Coded outcomes were no effect (53.3%), minor (33.7%), moderate (12.1%), major (0.9%) and no deaths. Moderate/major outcomes occurred most often with ziprasidone (20.5%) and olanzapine (19.0%) and least often with quetiapine (5.3%) and risperidone (10.9%).

DISCUSSION AND CONCLUSION

Overall outcomes were favorable, with major toxicity in <1% of exposures. Risperidone and quetiapine exposures resulted in less toxicity. This finding may be attributed to higher frequency of therapeutic errors for risperidone but the reason for less toxicity with quetiapine is unclear.

Antidepressant or Antipsychotic Overdose in the Intensive Care Unit - Identification of Patients at Risk

It is often advised that patients who have ingested an overdose of antidepressants (AD) or antipsychotics (AP) are monitored with continuous ECG for minimum of 12-24 hr. These patients are often observed in an ICU. Our aim was to identify the number of patients with AD and/or AP overdose without adverse signs at hospital admission that turned out to need intensive care treatment. The effect of the antidepressants overdose risk assessment (ADORA) system was evaluated in patients with antidepressant as well as antipsychotic overdose. Our hypothesis was that patients with low ADORA do not need intensive care treatment. This retrospective study was conducted in adult patients admitted to the ICU at Odense University Hospital after an overdose with AP and/or AD between 1 January 2009 and 1 September 2014. Patients with predefined adverse signs in the emergency department were excluded due to obvious need of intensive care. Of the 157 patients included, 12 patients (8%) developed events during the ICU stay. Only 3 patients received intubation, vasoactive drugs and/or dialysis. None developed ventricular dysrhythmias. There were no fatalities. All the patients with low-risk assessment by ADORA within the first 6 hr did not develop events within the first 24 hr after hospital admission. The vast majority of patients with AD and/or AP overdose and no adverse signs at admission did not require intensive care treatment. Low-risk ADORA identified patients with antidepressant as well as antipsychotic overdose who would not require initial intensive care treatment. This is the first time the ADORA system has been evaluated in patients with antidepressant as well as antipsychotic overdose.

Coma After Quetiapine Fumarate Intentional Overdose in a 71-year-old Man: A Case Report

A 71-year-old man developed coma with severe respiratory failure, hypotension, and tachycardia induced by the intentional ingestion of quetiapine fumarate extended release (XR) 20 g. At the time, he had been treated for bipolar depression with venlafaxine 75 mg/day, lamotrigine 100 mg/day, pregabalin 75 mg/day, and quetiapine XR 400 mg/day for approximately 1 year. Comorbidities were hypertension treated with metoprolol, diabetes mellitus type 2 treated with metformin, and benign prostatic hyperplasia treated with silodosin. In the emergency room, about 4 h after ingestion of quetiapine fumarate XR, the presenting symptomatology was characterized by coma (Glasgow Coma Scale score 3), hypotension (blood pressure [BP] 90/60 mmHg), tachycardia (electrocardiogram [ECG] showed sinus tachycardia with heart rate 120 beats per minute and a QTc of 499 ms). A gastric lavage was performed and activated charcoal 50 g and magnesium sulfate 30 g was administered. About 6 h after ingestion, he developed marked desaturation and underwent mechanical ventilation; 13 h after ingestion, a severe hypotensive episode followed (BP 70/40), which was treated with an infusion of ringer lactate 500 cc. On the 3rd day after intentional overdose, an episode of agitation occurred; 4 days after ingestion, the quetiapine plasma level was found to be 42 ng/ml (within therapeutic range). At 5 days after ingestion, the patient developed septicemia caused by staphylococci (probably originating from the central vein catheter), which was treated with antibiotic therapy. On days 10 and 18 after the suicide attempt, two episodes of paroxysmal supraventricular tachycardia (PSVT) occurred and were successfully treated with intravenous adenosine triphosphate. The patient recovered completely without residual symptoms. In line with literature data, in this case report, symptoms of quetiapine overdose were tachycardia, agitation, hypotension, QT interval prolongation, and coma. A causal relationship between PSVT and quetiapine intoxication seems quite unlikely due to the drug level.

Ventricular dysrhythmias associated with poisoning and drug overdose: a 10-year review of statewide poison control center data from California

BACKGROUND

Ventricular dysrhythmias are a serious consequence associated with drug overdose and chemical poisoning. The risk factors for the type of ventricular dysrhythmia and the outcomes by drug class are not well documented.

OBJECTIVE

The aim of this study was to determine the most common drugs and chemicals associated with ventricular dysrhythmias and their outcomes.

METHODS

We reviewed all human exposures reported to a statewide poison control system between 2002 and 2011 that had a documented ventricular dysrhythmia. Cases were differentiated into two groups by type of arrhythmia: (1) ventricular fibrillation and/or tachycardia (VT/VF); and (2) torsade de pointes (TdP).

RESULTS

Among the 300 potential cases identified, 148 cases met the inclusion criteria. Of these, 132 cases (89%) experienced an episode of VT or VF, while the remaining 16 cases (11%) had an episode of TdP. The most commonly involved therapeutic classes of drugs associated with VT/VF were antidepressants (33/132, 25%), stimulants (33/132, 25%), and diphenhydramine (16/132, 12.1%). Those associated with TdP were antidepressants (4/16, 25%), methadone (4/16, 25%), and antiarrhythmics (3/16, 18.75%). Drug exposures with the greatest risk of death in association with VT/VF were antidepressant exposure [odds ratio (OR) 1.71; 95% confidence interval (CI) 0.705-4.181] and antiarrhythmic exposure (OR 1.75; 95% CI 0.304-10.05), but neither association was statistically significant. Drug exposures with a statistically significant risk for TdP included methadone and antiarrhythmic drugs.

CONCLUSIONS

Antidepressants and stimulants were the most common drugs associated with ventricular dysrhythmias. Patients with suspected poisonings by medications with a high risk of ventricular dysrhythmia warrant prompt ECG monitoring.

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.

Trends in quetiapine use and non-fatal quetiapine-related ambulance attendances

INTRODUCTION AND AIMS

Concern about the non-medical use of quetiapine and related acute harms is growing. Case series cite quetiapine as a potential drug of misuse, while recent research questions its relative safety in comparison with other atypical antipsychotic preparations. This paper explores population-level patterns of quetiapine-related ambulance attendances over time, identifying associated risk factors and potential subpopulations at-risk of acute harms.

DESIGN AND METHODS

A retrospective analysis of quetiapine-, olanzapine- and risperidone-related ambulance attendances in metropolitan Melbourne and prescription data in Victoria, Australia. Trends in ambulance attendance and prescription rates, attendance characteristics, and associated risk factors were explored from 2001 to 2010.

RESULTS

Quetiapine was consistently associated with substantially higher rates of ambulance attendances relative to prescription availability than olanzapine or risperidone. Quetiapine prescribing rates increased at a significantly greater magnitude than olanzapine or risperidone, leading to substantial increases in quetiapine attendances by population. Quetiapine-related attendances were associated with concurrent heroin and opioid replacement therapy toxicity, history of heroin and alcohol misuse, mood disorders, low Glasgow Coma Scale and women.

DISCUSSION AND CONCLUSIONS

Trends in quetiapine-related ambulance attendances indicate rising community-level harms and greater harm relative to other atypical antipsychotics, while prescription patterns suggest increasing quetiapine availability. The association of quetiapine-related attendances with concurrent heroin and opioid replacement therapy toxicity as well as previous heroin and alcohol misuse suggest illicit and poly-drug users are a subpopulation at greater risk of quetiapine-related harms, consistent with emerging evidence of the use, misuse and diversion of quetiapine.

Overdose of atypical antipsychotics: clinical presentation, mechanisms of toxicity and management

Historically, treatment for schizophrenia focused on sedation. The advent of the typical antipsychotics resulted in treatment aimed specifically at the underlying disease, but these agents were associated with numerous adverse effects, and were not particularly effective at treatment of the negative symptoms of schizophrenia. As a result, numerous atypical agents have been developed over the past 2 decades, including several agents within the past 5 years. Overdose of antipsychotics remains quite common in Western society. In 2010, poison control centres in the US received nearly 43,000 calls related to atypical antipsychotics alone. Due to underreporting, the true incidence of overdose with atypical antipsychotics is likely much greater. Following overdose of an atypical antipsychotic, the clinical effects observed, such as CNS depression, tachycardia and orthostasis are largely predictable based on the unique receptor binding profile of the agent. This article, which focuses on the atypical antipsychotics commonly used in the treatment of schizophrenia, discusses the features commonly encountered in overdose. Specifically, agents that result in QT prolongation and the corresponding potential for torsades de pointes, as well as unique features encountered with the various medications are discussed. The diagnosis of this overdose is largely based on history. Routine use of drug screens is unlikely to be beneficial. The primary goal of management is aggressive supportive care. Patients with significant CNS depression with associated loss of airway reflexes and respiratory failure need advanced airway management. Hypotension should be treated first with intravenous fluids, with the use of direct acting vasopressors reserved for persistent hypotension. Benzodiazepines should be used for seizures, with barbiturates used for refractory seizures. Intravenous magnesium can be administered for patients with a corrected QT interval exceeding 500 milliseconds.

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.

Toxicology and overdose of atypical antipsychotics

BACKGROUND

Second-generation antipsychotic medications, or "atypical antipsychotics," are now first-line therapy in the treatment of schizophrenia and other psychotic disorders, and are additionally being used in a wide array of other psychiatric and non-psychiatric conditions in both adults and children. Overdose is frequently reported to poison control centers.

OBJECTIVES

We review the toxicology and general management of poisonings involving the atypical antipsychotic medications.

DISCUSSION

The most serious toxicity involves the cardiovascular system and the central nervous system. All typical and atypical antipsychotics cause sedation, which is pronounced in overdose. The most common cardiovascular effects that occur after atypical antipsychotic overdose are tachycardia, mild hypotension, and prolongation of the QTc interval. Other clinical syndromes in overdose include neuroleptic malignant syndrome (NMS) and antimuscarinic delirium. Seizures may be observed. No antidotes exist for these poisonings, but they most often do well with supportive care.

CONCLUSION

Antipsychotic overdose produces a gamut of manifestations that affect multiple organ systems. Treatment is primarily supportive. Specific therapies for NMS, hypotension, and seizures are discussed.

Case report: successful lipid resuscitation in multi-drug overdose with predominant tricyclic antidepressant toxidrome

We report a case of profound neurologic and cardiovascular manifestations of tricyclic antidepressant intoxication following self-poisoning with multiple pharmaceuticals including amitriptyline in excess of 43 mg/kg, in a 51-year-old male. Institution of mechanical ventilation, volume expansion, systemic alkalinisation (pH 7.51), and intermittent bolus metaraminol resulted in QRS narrowing but failed to resolve the developed shock. One 100-ml bolus of 20% lipid emulsion followed by a further 400 ml over 30 min was administered with restoration of haemodynamic stability, thereby curtailing the need for ongoing vasopressor medications. Assayed blood levels were consistent with the 'lipid sink' being a major effecter in the observed improvement.

Probable quetiapine-mediated prolongation of the QT interval

PURPOSE

QT prolongation can occur with both first- (FGA) and second-generation antipsychotics (SGA). QT prolongation was identified in an adult patient who presented to the emergency room with schizophrenia, fluid and electrolyte imbalances, and pneumonia. Quetiapine, an SGA, was a component of the pharmacotherapy regimen. Based on the Naranjo adverse drug reaction probability scale rating criteria, a probable causal association was made.

METHODS

PubMed and Ovid were searched using the terms antipsychotic, psychotropic, QT interval, corrected QT interval (QTc) prolongation, and quetiapine. References were examined for additional articles related to antipsychotic drugs and the QT interval.

DISCUSSION

In this patient, the use of quetiapine was identified as a contributing factor in QT prolongation. Prior QT prolongation was experienced with ziprasidone, another SGA. The antidepressant and dose remained consistent throughout the inpatient course of treatment. Other risk factors in this patient included hypokalemia, dehydration, pneumonia, age, gender, and concurrent usage of an antidepressant. Dual psychiatric diagnoses, preexisting cardiovascular disease, and electrolyte disturbances may increase this risk potential.

CONCLUSION

Psychiatric patients may be more at risk of cardiovascular complications, such as QT interval prolongation. The pharmacist can help evaluate risk factors and provide input into the care of all patients, particularly those identified as at risk.

Survival from coma induced by an intentional 36-g overdose of extended-release quetiapine

Quetiapine is a second-generation antipsychotic drug approved for the treatment of bipolar disorders and schizophrenia. Acute quetiapine overdose is rare, and quetiapine has long been thought to be safer than other antipsychotics. Nevertheless, as reported in the literature, the severity of the effect of quetiapine overdose has not been associated with a high serum concentration of the drug or with the reported ingested dose. In this article, we report a case of survival from coma induced by a massive extended-release (XR) quetiapine ingestion at a dose greater than reported in some previous fatal cases. A 34-year-old woman with chronic schizophrenia ingested 36 g of quetiapine fumarate XR for attempted suicide. She was initially lethargic, but her clinical conditions rapidly deteriorated and she collapsed unconscious. The woman was taken to the nearest hospital, where the medical emergency team found her in deep coma with response only to deep painful stimuli (Glasgow Coma Scale 9). An endotracheal tube was inserted for airway protection, and the patient was transferred to a critical care area for ventilatory support and maintenance of hydration status and electrolytic balance. Spontaneous breathing was restored in approximately 36 hours, and a few days later, she was discharged without reporting clinical complications. This is the first case of coma induced by an intentional 36-g overdose of quetiapine XR. Given the widespread use of quetiapine and the lack of information about its toxicity in overdose, this case report reinforces the importance of closely monitoring patients taking quetiapine and helps to better define the safety of this drug.