Association Between Selective Serotonin-Reuptake Inhibitors, Second-Generation Antipsychotics, and Neuroleptic Malignant Syndrome

Optimizing antidepressant and clozapine co-prescription in clinical practice: A systematic review and expert recommendations

OBJECTIVES

To synthesize the information relevant for clinical practice on clozapine-antidepressant co-prescription concerning pharmacokinetic drug-drug interactions (DDI), adverse drug reactions (ADRs) associated with the co-prescription, antidepressant add-on for clozapine-resistant symptoms and antidepressant add-on for clozapine-induced ADRs.

METHODS

Articles were identified with MEDLINE, Web of Sciences and PsycINFO search from inception through April 2023. Data were synthesized narratively.

RESULTS

ADRs are most often induced by the co-prescription of antidepressants that inhibit CYP enzymes (fluvoxamine, fluoxetine, paroxetine). Fluvoxamine add-on is hazardous because of its potent inhibition of clozapine metabolism and has few indications (lowering daily number of clozapine tablets, reducing norclozapine-induced metabolic disturbances and other dose-dependent clozapine-induced ADRs). ADR frequency may be reduced by therapeutic drug monitoring and knowledge of other factors impacting clozapine metabolism (pneumonia, inflammation, smoking, etc.). Improvement of negative symptoms is the most documented beneficial effect of antidepressant add-on for clozapine-resistant psychotic symptoms. The add-on antidepressant should be chosen according to its safety profile regarding DDI with clozapine: antidepressants inhibiting clozapine metabolism or increasing the anticholinergic load should be avoided. Other indications of antidepressant add-on (affective or obsessive compulsive symptoms, sialorrhea, and enuresis) are poorly documented.

CONCLUSION

Antidepressant add-on to clozapine is associated with potential benefits in clozapine users as this strategy may contribute to reduce the burden of clozapine-resistant symptoms or of clozapine-induced ADRs. Further studies are needed to determine whether antidepressant add-on can reduce the risk of clozapine discontinuation.

Differentiating tardive dyskinesia: a video-based review of antipsychotic-induced movement disorders in clinical practice

Accurate diagnosis and appropriate treatment of tardive dyskinesia (TD) are imperative, as its symptoms can be highly disruptive to both patients and their caregivers. Misdiagnosis can lead to incorrect interventions with suboptimal or even deleterious results. To aid in the identification and differentiation of TD in the psychiatric practice setting, we review its clinical features and movement phenomenology, as well as those of other antipsychotic-induced movement disorders, with accompanying links to illustrative videos. Exposure to dopamine receptor blocking agents (DRBAs) such as antipsychotics or antiemetics is associated with a spectrum of movement disorders including TD. The differential diagnosis of TD is based on history of DRBA exposure, recent discontinuation or dose reduction of a DRBA, and movement phenomenology. Common diagnostic challenges are the abnormal behaviors and dyskinesias associated with advanced age or chronic mental illness, and other movement disorders associated with DRBA therapy, such as akathisia, parkinsonian tremor, and tremor related to use of mood stabilizing agents (eg, lithium, divalproex). Duration of exposure may help rule out acute drug-induced syndromes such as acute dystonia or acute/subacute akathisia. Another important consideration is the potential for TD to present together with other drug-induced movement disorders (eg, parkinsonism, parkinsonian tremor, and postural tremor from mood stabilizers) in the same patient, which can complicate both diagnosis and management. After documentation of the phenomenology, severity, and distribution of TD movements, treatment options should be reviewed with the patient and caregivers.

Atypical Neuroleptic Malignant Syndrome in the Setting of Quetiapine Overdose: A Case Report and Review of the Literature

Neuroleptic malignant syndrome (NMS) is a rare and life-threatening emergency. The condition is largely iatrogenic and is often precipitated by medications such as antipsychotics. First-generation antipsychotics are more likely to cause NMS than second-generation antipsychotics. The literature lacks an objective measure for NMS diagnosis. Instead, the diagnosis relies largely on the recognition of characteristic symptoms in the presence of an inciting medication. Additional challenges exist with concomitant disease processes and toxicities that may distort the clinical picture. Here, we report a case of a 44-year-old Caucasian man who presented with atypical NMS in the setting of quetiapine overdose. The patient remained uncharacteristically afebrile throughout his admission. Although the patient recovered, extended delays in identification and management can contribute to an increased risk of morbidity and mortality.

Neuroleptic malignant syndrome in patients with cancer: a systematic review

BACKGROUND

Antipsychotics potentially cause a low incidence of the side effect called neuroleptic malignant syndrome (NMS), which has a high mortality rate. However, few studies on NMS among patients with cancer exist.

AIMS

We aimed to examine the characteristics of antipsychotic-induced NMS among patients with cancer.

METHODS

We conducted a systematic review of published reports on NMS described during the treatment of patients with any type of cancer. Articles were identified by a comprehensive search of PubMed, Web of Science, the Cochrane Library and reference lists from relevant articles published until 25 December 2019. Original articles or case reports on humans published in English were included. This review summarises the symptoms, characteristics, treatment course and prognosis of patients with cancer with NMS.

RESULTS

Eleven patients with various cancer types from ten case reports published from 1988 to 2013 met the eligibility criteria. Mean age of the 11 patients was 52.5 (range, 32-83) years. NMS developed mostly during the postoperative period, and haloperidol and D2 receptor antagonists were determined as the common causative drugs. Ten patients survived following treatment that mostly involved discontinuing the causative drugs and administering dantrolene, if necessary.

CONCLUSION

Although NMS intrinsically has a low incidence and high mortality, only few reports were available, with most patients surviving after early detection and appropriate treatment. Healthcare providers should consider NMS development while prescribing antipsychotics to ensure prompt recognition of the condition and rapid treatment for preventing unnecessary deaths.

Perioperative Considerations for Patients With Major Depressive Disorder Undergoing Surgery

In the United States, approximately 15% of adults suffer from major depressive disorder (MDD), which results in an annual cost of over $200 billion per year. In the perioperative setting, MDD is associated with increased morbidity and mortality. The exact causes of the increase in adverse outcomes are unknown. Major depression affects virtually all major systems in the human body, and most antidepressants affect dopamine, norepinephrine, and serotonin levels or alter their target receptors. Unfortunately, anesthesia and medications used in the perioperative period affect the same neurotransmitters. As a result, patients with MDD are at an increased risk for cardiovascular effects, altered thermoregulation, and postoperative cognitive dysfunction. To determine when to continue or hold antidepressants preoperatively and avoid potential drug interactions, perioperative providers must understand the pharmacological action of antidepressants. This article reviews the pathophysiology of MDD, mechanism of action of antidepressants, and perioperative considerations for patients on antidepressant medications.

[Indirect and mixed mechanisms of action in toxic myopathies]

Toxic myopathies are a group of pathologies characterized by a structural and/or functional disturbance of muscles induced by an exogenous agent. The most frequent are those induced by drugs used in clinical practice. Illegal drugs, pesticides, solvents, metals and even physical and gaseous agents can cause this kind of disease and exert toxicity on muscle tissues. Some toxins from animals, plants or micro-organisms are potent myotoxic agents, which can lead to fatal complications. Respiratory arrest and rhabdomyolysis are often referred to as the ultimate complications of these pathologies. Several mechanisms of action can be triggered. Muscles may represent a direct target for exogenous agents by acting on the myocyte components or indirect target by inducing functional disorders. These disorders are triggered by neuromuscular interferences (organophosphates, antipsychotics, curares, etc.) and endocrine (glucocorticoids and ethyl alcohol), immune (d-penicillamine and statins) and hydroelectrolytic system dysfunctions (diuretics, laxatives and toluene). Direct and indirect effects can be induced by the same toxic agent, such as carbon monoxide, glucocorticoids, ethyl alcohol and some toxins from snake venoms.

[Neuroleptic malignant syndrome]

BACKGROUND

Neuroleptic malignant syndrome (NMS) is a rare but severe undesired complication of psychopharmacological treatment. The mortality has shown a significant decrease since its first description. Knowledge of NMS is important for every clinician because of the need for rapid diagnosis and treatment.

OBJECTIVE

This article presents a review and critical appraisal of the current study situation for NMS. Recommendations for diagnostics, differential diagnostics and treatment are presented particularly from a clinical perspective.

MATERIAL AND METHODS

A literature review with the keywords "neuroleptic malignant syndrome", "Malignes neuroleptisches Syndrom" and various psychotropic drugs was performed in PubMed. The database of the Working Group for Pharmaceutical Treatment of Psychiatric Diseases (Arbeitsgemeinschaft für Arzneimitteltherapie bei psychiatrischen Erkrankungen, AGATE) was analyzed with respect to registered cases of the undesired side effect NMS.

RESULTS

In contrast to the first description, which also led to the name, there are now case reports of clinical conditions similar to NMS, which were obviously triggered by several groups of psychotropic drugs not just antipsychotic agents (German: Neuroleptika). Treatment recommendations exist whereby the effectiveness cannot always be scientifically substantiated; however, it is still undisputed that a rapid initiation of treatment is of great importance.

DISCUSSION

The psychiatrist must be familiar with the symptoms of NMS, its differential diagnosis and the therapeutic options for a rapid and effective treatment. Further studies are urgently needed for scientific substantiation of the pathophysiology of NMS and to develop evidence-based guidelines for treatment.

Neuroleptic malignant syndrome and serotonin syndrome

The clinical manifestation of drug-induced abnormalities in thermoregulation occurs across a variety of drug mechanisms. The aim of this chapter is to review two of the most common drug-induced hyperthermic states, serotonin syndrome and neuroleptic malignant syndrome. Clinical features, pathophysiology, and treatment strategies will be discussed, in addition to differentiating between these two syndromes and differentiating them from other hyperthermic or febrile syndromes. Our goal is to both review the current literature and to provide a practical guide to identification and treatment of these potentially life-threatening illnesses. The diagnostic and treatment recommendations made by us, and by other authors, are likely to change with a better understanding of the pathophysiology of these syndromes.

Malignant Syndrome and Serotonin Syndrome in a General Hospital Setting: Clinical Features, Frequency and Prognosis

Objective The differences in the frequency and clinical features of malignant syndrome (MS) and serotonin syndrome (SS) in same population have only rarely been reported. To report the frequency and clinical features of MS and SS in a general hospital setting. Methods The clinical and laboratory features of patients with MS and those with SS, who were consecutively admitted to Chiba Rosai Hospital, during the past 4.5 years were reviewed. Results Of the 2005 patients admitted, MS was observed in 16 patients (0.8%) and SS in 2 (0.1%). In the 16 patients with MS, the underlying disorder included depression (n = 5), and dementia or parkinsonism (n = 11). The underlying etiology of the 2 patients with SS was depression. In 5 patients, MS was difficult to distinguish from SS because of overlapping symptoms and signs and/or treatments with both neuroleptic and serotoninergic drugs. Of the 16 patients with MS, 1 died, 1 remained wheelchair-bound, 4 were able to walk with assistance, and 10 regained their ability to ambulate independently. The 2 patients with SS recovered after cyproheptadine therapy and were discharged on foot. Conclusion MS occurs more frequently than SS in the general hospital setting. Underlying aetiologies in patients with MS were more common due to dementia or parkinsonism than in patients with psychiatric disorders. The differential diagnosis of MS and SS is often difficult and the diagnostic sensitivities largely differ for each of the diagnostic criteria. As a result, the establishment of new diagnostic criteria that specifically focus on distinguishing MS from SS is therefore required.

Drug-Induced Extrapyramidal Syndromes: Implications for Contemporary Practice

The development of drugs to treat psychosis is a fascinating nexus for understanding mechanisms underlying disorders of mind and movement. Although the risk of drug-induced extrapyramidal syndromes has been mitigated by the acceptance of less potent dopamine antagonists, expansive marketing and off-label use has increased the number of susceptible people who may be at risk for these neurologic effects. Clinicians need to be familiar with advances in diagnosis and management, which are reviewed herein. A better understanding of drug-induced effects on the motor circuit may improve patient safety, enhance antipsychotic effectiveness, and provide insights into mechanisms underlying antipsychotic activity in parallel brain circuits.

Neuroleptic Malignant Syndrome: A Review from a Clinically Oriented Perspective

Neuroleptic malignant syndrome (NMS) is a rare but potentially life-threatening side-effect that can occur in response to treatment with antipsychotic drugs. Symptoms commonly include hyperpyrexia, muscle rigidity, autonomic dysfunction and altered mental status. In the current review we provide an overview on past and current developments in understanding the causes and treatment of NMS. Studies on the epidemiological incidence of NMS are evaluated, and we provide new data from the Canada Vigilance Adverse Reaction Online database to elaborate on drug-specific and antipsychotic drug polypharmacy instances of NMS reported between 1965 and 2012. Established risk factors are summarized with an emphasis on pharmacological and environmental causes. Leading theories about the etiopathology of NMS are discussed, including the potential contribution of the impact of dopamine receptor blockade and musculoskeletal fiber toxicity. A clinical perspective is provided whereby the clinical presentation and phenomenology of NMS is detailed, while the diagnosis of NMS and its differential is expounded. Current therapeutic strategies are outlined and the role for both pharmacological and non-pharmacological treatment strategies in alleviating the symptoms of NMS are discussed.

Neuroleptic malignant syndrome following combination of sertraline and paroxetine: a case report

Neuroleptic malignant syndrome (NMS) is a rarely observed life-threatening medical condition due mostly to antipsychotic use. Additionally, a few case reports have suggested an association between NMS and the use of selective serotonin reuptake inhibitors (SSRIs) alone or in combination with antipsychotics. This case report presents a female patient developing NMS following the use of a combination of sertraline and paroxetine.

Movement disorders induced by antipsychotic drugs: implications of the CATIE schizophrenia trial

Drug-induced movement disorders have dramatically declined with the widespread use of second-generation antipsychotics, but remain important in clinical practice and for understanding antipsychotic pharmacology. The diagnosis and management of dystonia, parkinsonism, akathisia, catatonia, neuroleptic malignant syndrome, and tardive dyskinesia are reviewed in relation to the decreased liability of the second-generation antipsychotics contrasted with evidence from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) Schizophrenia Trial. Data from the CATIE trial imply that advantages of second-generation antipsychotics in significantly reducing extrapyramidal side effects compared with haloperidol may be diminished when compared with modest doses of lower-potency first-generation drugs.

Venlafaxine-associated serotonin syndrome causing severe rhabdomyolysis and acute renal failure in a patient with idiopathic Parkinson disease

A 43-year-old male patient with idiopathic Parkinson disease, on dopaminergic therapy, was admitted with confusion and agitation, diaphoresis, and hyperkinesia after the commencement of the serotonin-noradrenaline reuptake inhibitor venlafaxine 2 weeks prior for depression. He was found to have severe rhabdomyolysis and developed acute renal failure. The most likely diagnosis was serotonin syndrome induced by venlafaxine, although neuroleptic malignant syndrome was also considered. The differential diagnosis, atypical features in this presentation, and possible mechanisms are discussed.

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

INTRODUCTION

Current data regarding risk factors of neuroleptic malignant syndrome (NMS) are limited. This study aims to examine factors associated with increased risk of NMS in patients with bipolar disorder.

METHODS

A retrospective, population-based, case-control study was performed using a medical claims database covering January 1998 to December 2002. Fifty cases with a diagnosis of NMS were identified and matched with 800 controls. Conditional logistic regression analysis was used to estimate crude and adjusted odds ratios (ORs) of risk of NMS.

RESULTS

Antipsychotic use was associated with an increased risk of NMS after controlling for other pharmacologic and clinical factors (OR = 2.36, 95% CI = 1.08-5.19). Other factors associated with an increased risk of NMS included being male (OR = 2.07, 95% CI = 1.07-4.02), confusion (OR = 2.91, 95% CI = 1.17-7.28), dehydration (OR = 3.99, 95% CI = 1.50-10.57), delirium (OR = 4.93, 95% CI = 2.07-11.72), and extrapyramidal symptoms (OR = 3.50, 95% CI = 1.10-11.09).

CONCLUSIONS

Given the widespread use of antipsychotics for the treatment of bipolar disorder, clinicians should be vigilant of the potential pharmacologic and clinical factors associated with increased risk of NMS in patients with bipolar disorder.

The elderly safety imperative and antipsychotic usage

Behavioral and psychotic symptoms are common problems in older adults, and as the population ages, understanding the benefits and risks of antipsychotic usage is increasingly important. In this age group, psychotic symptoms may occur in patients with dementia or as part of schizophrenia, mood disorders, delirium, or delusional disorder. Various antipsychotics have been studied in older adults with psychotic symptoms, demonstrating mixed, but real, benefit, especially in relation to carefully selected patients. Caution is required because of the potential side effects and risks, which include increased mortality and cardiovascular and cerebrovascular events. This article reviews the use of antipsychotics in older adults, with emphasis on the risks and side effects, particularly in dementia patients with behavioral and psychotic symptoms.

Adenoviral vectors for highly selective gene expression in central serotonergic neurons reveal quantal characteristics of serotonin release in the rat brain

Background

5-hydroxytryptamine (5 HT, serotonin) is one of the key neuromodulators in mammalian brain, but many fundamental properties of serotonergic neurones and 5 HT release remain unknown. The objective of this study was to generate an adenoviral vector system for selective targeting of serotonergic neurones and apply it to study quantal characteristics of 5 HT release in the rat brain.

Results

We have generated adenoviral vectors which incorporate a 3.6 kb fragment of the rat tryptophan hydroxylase-2 (TPH-2) gene which selectively (97% co-localisation with TPH-2) target raphe serotonergic neurones. In order to enhance the level of expression a two-step transcriptional amplification strategy was employed. This allowed direct visualization of serotonergic neurones by EGFP fluorescence. Using these vectors we have performed initial characterization of EGFP-expressing serotonergic neurones in rat organotypic brain slice cultures. Fluorescent serotonergic neurones were identified and studied using patch clamp and confocal Ca²⁺ imaging and had features consistent with those previously reported using post-hoc identification approaches. Fine processes of serotonergic neurones could also be visualized in un-fixed tissue and morphometric analysis suggested two putative types of axonal varicosities. We used micro-amperometry to analyse the quantal characteristics of 5 HT release and found that central 5 HT exocytosis occurs predominantly in quanta of ~28000 molecules from varicosities and ~34000 molecules from cell bodies. In addition, in somata, we observed a minority of large release events discharging on average ~800000 molecules.

Conclusion

For the first time quantal release of 5 HT from somato-dendritic compartments and axonal varicosities in mammalian brain has been demonstrated directly and characterised. Release from somato-dendritic and axonal compartments might have different physiological functions. Novel vectors generated in this study open a host of new experimental opportunities and will greatly facilitate further studies of the central serotonergic system.

Recent Publications on Medications and Pharmacy

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