Risk of neuroleptic malignant syndrome in patients with bipolar disorder: a retrospective, population-based case-control study

Antipsychotics and Risk of Neuroleptic Malignant Syndrome: A Population-Based Cohort and Case-Crossover Study

BACKGROUND

Neuroleptic malignant syndrome (NMS) is a rare and acute adverse drug reaction associated with antipsychotic therapy. However, few data on the risk and epidemiology of NMS are available.

OBJECTIVES

The aim of this study was to ascertain the incidence risk and all-cause mortality of NMS associated with antipsychotic use, and to assess the association of recent antipsychotic exposure and NMS.

METHODS

We did a population-based study using data from the Hong Kong Hospital Authority's Clinical Data Analysis and Reporting System database. Cases had a first diagnosis of NMS between 1 January 2004 and 30 November 2017. A case-crossover analysis was used to compare antipsychotic exposure 30 days before the diagnosis of NMS (index date) and a reference period 91-120 days before the index date. To adjust for potential time trends in antipsychotic exposure, we sampled from cases to match current cases and future cases, and further adjusted for select medications and acute medical conditions.

RESULTS

297,647 patients were prescribed antipsychotics, and the incidence risk of NMS was 0.11%. Of the 336 cases included in the case-crossover analysis, 20 (6%) died within 30 days after the index date; only one case had NMS recorded as the primary cause of death. When compared with the reference period, cases were more frequently prescribed multiple antipsychotics (15.8% vs 26.8%; standardized mean difference [SMD] 0.27) and short-acting injectable antipsychotics (3.6% vs 13.7%; SMD 0.37) during the 30 days prior to the diagnosis of NMS. Odds ratios for antipsychotic exposure in the case-crossover, case-crossover adjusted for time trend, and case-crossover adjusted for time trend and potential confounders analysis were 8.00 (95% confidence interval 3.42-18.69), 5.88 (2.46-14.04), and 4.77 (1.95-11.66).

CONCLUSIONS

Our results suggest that recent use of antipsychotics is associated with NMS. Although a case-only design inherently controls for confounding by time-invariant factors, residual confounding by acute medical conditions with similar presentations to NMS cannot be fully excluded.

Exertional Heatstroke in a Marathon Runner Complicated by Concurrent Use of an Antipsychotic Medication Affecting Thermoregulation

We report the case of a half-marathon runner who presented with exertional heatstroke (EHS), whose management was confounded by concurrent treatment of his bipolar disorder with olanzapine. Antipsychotics can have a profound effect on thermoregulation and can cause athletes to present with features of neuroleptic malignant syndrome in the setting of EHS. It is vital for medical providers to consider the thermoregulatory effects of all medications, including antipsychotics, when providing care during sporting events.

Neuroleptic malignant syndrome: evaluation of drug safety data from the AMSP program during 1993-2015

Neuroleptic malignant syndrome (NMS) is a rare, but severe adverse drug reaction of drugs with anti-dopaminergic properties. The main symptoms are fever and rigor. In addition, other symptoms such as creatine kinase elevation, alteration of consciousness and various neurological symptoms may occur. A total of 52 NMS cases have been documented in the drug safety program 'Arzneimittelsicherheit in der Psychiatrie' from 1993 to 2015. We calculated incidences and analyzed imputed substances and additional risk factors to study the impact of changing therapy regimes. The overall incidence was 0.16‰. High-potency first-generation antipsychotics (FGAs) had the highest incidences, e.g. flupentixol with 0.61‰. Second-generation antipsychotics (SGAs) had lower incidences. Low-potency FGAs had very low incidences, comparable to SGAs, but in contrast to SGAs, had not been imputed alone in any case of NMS. Preexisting organic pathologies of the central nervous system, lithium treatment, infection/exsiccosis and the withdrawal of medication with anticholinergic properties or alcohol were found to be additional risk factors. With the increasing use of SGAs, one should always be aware of the risk of NMS. Better suited diagnostic criteria for 'atypical NMS' would lead to a better understanding and, therefore, to improved treatment possibilities.

A systematic review of sex and age factors in neuroleptic malignant syndrome diagnosis frequency

OBJECTIVE

To examine sex and age distributions in neuroleptic malignant syndrome (NMS) patients based on a systematic literature review.

METHOD

EMBASE and PubMed databases were searched to identify any observation of NMS published from January 1, 1998 through November 1, 2014 that was accessible and interpretable (using language translation software). Redundant and equivocal reports were excluded. Sex ratio and age distributions were examined using standard graphical techniques and measures of association.

RESULTS

Twenty-eight independent sex ratio estimates were included. Males predominated in most (75%) estimates with an overall median sex ratio of 1.47 (95% CI, 1.20-1.80). NMS incidence peaked at age 20-25 years and declined steadily thereafter, with males consistently outnumbering females at all but the oldest age intervals.

CONCLUSION

NMS patients are 50% more likely to be males, and NMS is most likely to occur in young adulthood.

Second-generation antipsychotics and neuroleptic malignant syndrome: systematic review and case report analysis

BACKGROUND

Neuroleptic malignant syndrome (NMS) is a rare, severe, idiosyncratic adverse reaction to antipsychotics. Second-generation antipsychotics (SGAs) were originally assumed to be free from the risk of causing NMS, however several cases of NMS induced by SGAs (SGA-NMS) have been reported.

OBJECTIVES

The aim of this study was to systematically review available studies and case reports on SGA-NMS and compare the presentation of NMS induced by different SGAs.

DATA SOURCES

Citations were retrieved from PubMed up to November 2013, and from reference lists of relevant citations.

STUDY ELIGIBILITY CRITERIA

Eligibility criteria included (a) primary studies reporting data on NMS, with at least 50 % of the sample receiving SGAs; or (b) case reports and case reviews reporting on NMS induced by SGA monotherapy, excluding those due to antipsychotic withdrawal.

STUDY APPRAISAL AND SYNTHESIS METHODS

A standardized method for data extraction and coding was developed for the analysis of eligible case reports.

RESULTS

Six primary studies and 186 individual cases of NMS induced by SGAs were included. Primary studies suggest that SGA-NMS is characterized by lower incidence, lower clinical severity, and less frequent lethal outcome than NMS induced by first-generation antipsychotics. Systematic analysis of case reports suggests that even the most recently marketed antipsychotics are not free from the risk of inducing NMS. Furthermore, clozapine-, aripiprazole- and amisulpride-induced NMS can present with atypical features more frequently than other SGA-NMS, i.e. displaying less intense extrapyramidal symptoms or high fever.

LIMITATIONS

Case reports report non-systematic data, therefore analyses may be subject to bias.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Clinicians should be aware that NMS is virtually associated with all antipsychotics, including those most recently marketed. Although apparently less severe than NMS induced by older antipsychotics, SGA-NMS still represent a relevant clinical issue.

Retrospective chart review on exposure to psychotropic medications associated with neuroleptic malignant syndrome

OBJECTIVE

To investigate the association between neuroleptic malignant syndrome (NMS) and levels of antipsychotic exposure.

METHOD

Electronic health record data systematically screened from a large mental health service provider in southeast London provided 67 NMS cases which were individually matched with 254 controls on age, gender, and primary psychiatric diagnosis. Data on psychotropic agents, combinations, dose, and dose change of antipsychotic prescriptions over the preceding 5 (oral agents) or 15 days (depot agents) were extracted and compared between groups using conditional logistic regression models.

RESULTS

NMS was associated with higher number of antipsychotic agents used, use of first-generation agents or aripiprazole, use of first-generation agents only or cross-generation agents, and higher mean and maximum daily doses. In further analyses, associations with antipsychotics type remained significant when adjusted for dose, but those with dose were attenuated following adjustment for type. The specific use of haloperidol, aripiprazole, depot flupentixol, and benzodiazepines was independently associated with NMS. Non-white ethnicity was also found to be associated with NMS.

CONCLUSION

NMS was primarily associated with type of antipsychotic and polypharmacy rather than overall dose. Variation in risk by ethnicity requires further research.

Delirium followed by neuroleptic malignant syndrome in rehabilitation setting. Is it anger reaction before discharge?

Delirium and neuroleptic malignant syndrome (NMS) are two uncommon syndromes that are often unrecognized or misdiagnosed by the primary physicians as functional psychiatric disorders. The infrequency and the heterogeneity of clinical manifestation, progression and outcome with which those diagnoses are encountered (particularly in chronic rehabilitation settings) make them formidable diagnostic challenge. In this report, we present a case in which there was a misdiagnosis of delirium and NMS as functional psychiatric disorders. This report demonstrates the fact that early recognition and intervention in such cases are essential to prevent the grave outcome and potential fatality. The authors believe that there is a key role for the consulting psychiatrist in this area in providing diagnostic clarity and advice regarding management and ongoing staff education.

Canadian Network for Mood and Anxiety Treatments (CANMAT) and International Society for Bipolar Disorders (ISBD) collaborative update of CANMAT guidelines for the management of patients with bipolar disorder: update 2013

The Canadian Network for Mood and Anxiety Treatments published guidelines for the management of bipolar disorder in 2005, with updates in 2007 and 2009. This third update, in conjunction with the International Society for Bipolar Disorders, reviews new evidence and is designed to be used in conjunction with the previous publications.The recommendations for the management of acute mania remain largely unchanged. Lithium, valproate, and several atypical antipsychotic agents continue to be first-line treatments for acute mania. Monotherapy with asenapine, paliperidone extended release (ER), and divalproex ER, as well as adjunctive asenapine, have been added as first-line options.For the management of bipolar depression, lithium, lamotrigine, and quetiapine monotherapy, as well as olanzapine plus selective serotonin reuptake inhibitor (SSRI), and lithium or divalproex plus SSRI/bupropion remain first-line options. Lurasidone monotherapy and the combination of lurasidone or lamotrigine plus lithium or divalproex have been added as a second-line options. Ziprasidone alone or as adjunctive therapy, and adjunctive levetiracetam have been added as not-recommended options for the treatment of bipolar depression. Lithium, lamotrigine, valproate, olanzapine, quetiapine, aripiprazole, risperidone long-acting injection, and adjunctive ziprasidone continue to be first-line options for maintenance treatment of bipolar disorder. Asenapine alone or as adjunctive therapy have been added as third-line options.

Fluoxetine affects GluK2 editing, glutamate-evoked Ca(2+) influx and extracellular signal-regulated kinase phosphorylation in mouse astrocytes

BACKGROUND

We sought to study the effects of chronic exposure to fluoxetine - a selective serotonin reuptake inhibitor (SSRI) and specific 5-HT(2B) receptor agonist in astrocytes - on the expression of kainate receptors (GluK1-5) in cultured astrocytes and in intact brains in mice and on GluK2 editing by adenosine deaminase acting on RNA (ADAR), as well as the ensuing effects of fluoxetine on glutamate-mediated Ca(2+) influx and extracellular signal-regulated kinase (ERK)(1/2) phosphorylation in astrocytes.

METHODS

We performed reverse transcription-polymerase chain reaction (PCR) to assess mRNA expression. We analyzed RNA editing with amplification refractory mutation system PCR and complementary DNA sequencing. Protein expression and ERK phosphorylation were assessed using Western blots. We studied gene silencing with specific small interfering RNAs (siRNA), and we studied intracellular Ca(2+) using fluorometry.

RESULTS

All GluK subunits were present in the brain in vivo, and GluK2-5 subunits were present in cultured astrocytes. Fluoxetine upregulated GluK2 and ADAR2. Enhanced GluK2 editing by fluoxetine abolished glutamate-mediated increases in intra cellular Ca(2+) and ERK(1/2) phosphorylation. Enhanced editing of GluK2 was prevented by siRNA against the 5-HT(2B) receptor or ADAR2.

LIMITATIONS

Limitations of our study include the use of an in vitro system, but our cultured cells in many respects behave like in vivo astrocytes.

CONCLUSION

Fluoxetine alters astrocytic glutamatergic function.