Serotonin syndrome. A clinical update

Clinical Effects of Psychedelic Substances Reported to United States Poison Centers: 2012 to 2022

STUDY OBJECTIVE

Psychedelic substances use is increasing in the United States (US). The approval of new psychedelic drugs and legalization of natural psychedelic substances will likely further increase exposures and subsequent adverse events. The study objective is to describe the clinical effects, therapies, and medical outcomes of patients with psychedelic exposures reported to US poison centers.

METHODS

We performed a retrospective, cross-sectional study on psychedelic exposures reported to the National Poison Data System from January 1, 2012, to December 31, 2022. We categorized exposures into groups: hallucinogenic amphetamines, lysergic acid diethylamide, tryptamines (such as N, N-dimethyltryptamine), phencyclidine, hallucinogenic mushrooms, hallucinogenic plants, and ketamine and ketamine analogs. We summarized effects, treatments, and outcomes and evaluated associations with logistic regression and odds ratios.

RESULTS

Our sample included 54,605 cases. There were concomitant exposures in 41.1% (n=22,460) of cases. Hallucinogenic mushroom exposures increased most over the study period from 593 in 2012 to 1,440 in 2022. Overall, 27,444 (50.3%) psychedelic exposures had symptoms that required treatment, severe residual or prolonged symptoms, or death. Cardiovascular effects were common, especially with hallucinogenic amphetamine exposures (31.1%). Patients managed in or referred to a health care facility received medical therapies in 62.4% of cases, including sedation (32.9%) and respiratory interventions (10.3%).

CONCLUSION

Over half of psychedelic exposures reported to US poison centers had symptoms that required treatment, severe residual or prolonged symptoms, or death. Increases in psychedelic use may lead to increased frequency of adverse events and health care utilization.

Serotonin Syndrome Induced by Fentanyl Alone in an Adult Patient After Cardiac Surgery: A Case Report

Serotonin syndrome is a rare but potentially fatal condition characterized by altered mental status, autonomic hyperactivity, and neuromuscular abnormalities. Although fentanyl is known to be a causative agent of serotonin syndrome, most reports have shown that fentanyl-related serotonin syndrome is caused by multiple drug interactions, and only one case of serotonin syndrome caused by fentanyl alone has been reported in a pediatric patient. In this report, we describe a case of postoperative serotonin syndrome caused by fentanyl alone in an adult patient after cardiac surgery. A 66-year-old male was diagnosed with unstable angina pectoris and underwent off-pump coronary artery bypass grafting. Two hours after the intensive care unit (ICU) admission, he exhibited symptoms of sweating, tremors, and muscle rigidity. Four hours later, the body temperature rose to 40.0 °C, suggesting malignant hyperthermia or a similar condition. Dantrolene was administered to the patient, and all symptoms improved within several minutes. However, the patient experienced a relapse of symptoms every four to six hours, requiring additional dantrolene treatment each time. Although no other serotonergic agents were used, we suspected serotonin syndrome induced by fentanyl alone and discontinued its use on postoperative day three. Following the discontinuation of fentanyl, no further episodes were observed. The patient was discharged from the hospital without any complications on postoperative day 29. During a subsequent check-up, the patient was found to have a sternal dehiscence and underwent one-stage sternal reconstruction. General anesthesia was induced and maintained without the use of fentanyl. The patient was discharged 10 days after surgery without symptoms of serotonin syndrome. In a patient with postoperative hyperthermia and neuromuscular abnormalities, serotonin syndrome should be considered when fentanyl is administered. Dantrolene may be beneficial in managing serotonin syndrome caused by fentanyl alone and/or benzodiazepine resistance.

Serotonin syndrome presenting as acute dizziness with supine hypertension and orthostatic hypotension

Serotonin syndrome (SS) is a drug-induced clinical syndrome characterised by a combination of cognitive, neuromuscular and autonomic dysfunctions. The symptoms may include mild non-specific symptoms such as tremors and diarrhoea to coma and sudden death. Herein, we describe a case of SS in which acute dizziness was associated with supine hypertension and orthostatic hypotension. A man in his mid-30s had a 10-month history of anxiety, depression and chronic tension-type headache. He had been on amitriptyline (25 mg daily) and sertraline (50 mg daily). Increment of sertraline (75 mg daily) and amitriptyline (75 mg daily) and the addition of tramadol led to the development of acute severe dizziness. Physical examinations demonstrate supine hypertension and orthostatic hypotension. He also met the diagnostic criteria of SS. The administration of cyproheptadine provided a complete response to dizziness, supine hypertension, orthostatic hypotension and other clinical features of SS.

Serotonin syndrome treated with cyproheptadine using NPi from a digital pupillometer as a therapeutic indicator: A case report

RATIONALE

Serotonin syndrome is a potentially life-threatening condition resulting from the use of antidepressants, their interactions with other serotonergic medications, or poisoning. It presents with a triad of psychiatric, dysautonomic, and neurological symptoms and is sometimes fatal. While cyproheptadine is a specific treatment option, the optimal duration of its administration remains unclear. The purpose of this report is to quantitatively assess the endpoints of serotonin syndrome treatment. Based on the hypothesis that neurological pupil index (NPi) on a digital pupil recorder would correlate with the severity of the serotonin syndrome, we administered cyproheptadine using NPi as an indicator.

PATIENT CONCERNS

A patient with a history of depression was brought to our hospital after he overdosed on 251 tablets of serotonin and noradrenaline reuptake inhibitors.

DIAGNOSES

On day 3, the patient was diagnosed with serotonin syndrome.

INTERVENTIONS

Cyproheptadine syrup was administered at 4 mg every 4 hours. The NPi of the automated pupillometer was simultaneously measured. On day 5, the NPi exceeded 3.0 cyproheptadine was discontinued.

OUTCOMES

The patient was discharged on day 7.

LESSONS

The lack of considerable improvement during the treatment period suggests that the patient may have improved on his own. In this case, the relationship between NPi and the severity of serotonin syndrome could not be determined.

Examining the Interaction between Exercise, Gut Microbiota, and Neurodegeneration: Future Research Directions

Physical activity has been demonstrated to have a significant impact on gut microbial diversity and function. Emerging research has revealed certain aspects of the complex interactions between the gut, exercise, microbiota, and neurodegenerative diseases, suggesting that changes in gut microbial diversity and metabolic function may have an impact on the onset and progression of neurological conditions. This study aimed to review the current literature from several databases until 1 June 2023 (PubMed/MEDLINE, Web of Science, and Google Scholar) on the interplay between the gut, physical exercise, microbiota, and neurodegeneration. We summarized the roles of exercise and gut microbiota on neurodegeneration and identified the ways in which these are all connected. The gut-brain axis is a complex and multifaceted network that has gained considerable attention in recent years. Research indicates that gut microbiota plays vital roles in metabolic shifts during physiological or pathophysiological conditions in neurodegenerative diseases; therefore, they are closely related to maintaining overall health and well-being. Similarly, exercise has shown positive effects on brain health and cognitive function, which may reduce/delay the onset of severe neurological disorders. Exercise has been associated with various neurochemical changes, including alterations in cortisol levels, increased production of endorphins, endocannabinoids like anandamide, as well as higher levels of serotonin and dopamine. These changes have been linked to mood improvements, enhanced sleep quality, better motor control, and cognitive enhancements resulting from exercise-induced effects. However, further clinical research is necessary to evaluate changes in bacteria taxa along with age- and sex-based differences.

Therapeutic cyproheptadine regimen in serotonin syndrome: Complications after cardiovascular surgery

Serotonin syndrome can be a life-threatening condition that occurs from the overactivity of serotonin in the central nervous system. This report describes the use of cyproheptadine for the management of serotonin syndrome in a patient taking fluoxetine and bupropion, who received methylene blue for vasoplegia syndrome. A 61-year-old female taking fluoxetine and bupropion preoperatively was given a total of three doses of methylene blue 100 mg IV within a brief time frame during and after a planned coronary artery bypass graft surgery. Postoperatively, the patient was not following commands, was agitated and confused, febrile with diaphoresis, tachycardic, had muscle rigidity, and horizontal ocular clonus. The patient's presentation was most consistent with serotonin syndrome due to a drug-drug interaction. Cyproheptadine and supportive care were used successfully to treat serotonin syndrome, and the patient was discharged home 14 days postoperatively. Based on the literature, there is no standardized method of weaning cyproheptadine when used for serotonin syndrome. The patient in our case received a total of 188 mg of cyproheptadine over the course of 10 days and did not experience any side effects. This case highlights a potential dosing regimen that can be used for other patients.

Misdiagnosed psychiatric manifestations in a rare disease: a case report of secondary anxiety syndrome in Cushing's disease

Diagnosing and treating secondary psychiatric symptoms with accuracy can be challenging in clinical settings. In this case study, we report on a female patient with Cushing's disease who was misdiagnosed with anxiety disorder during her first psychiatric visit. Following initial ineffective psychiatric intervention, unexplained hypokalemia, and hypothyroidism, the patient visited the endocrinology clinic and was diagnosed with Cushing's disease. During the medical and surgical procedures that followed, high doses of psychotropic medication were continued to treat persisting anxiety. After discharge, the patient developed autonomic dysfunction and impaired consciousness. Upon readmission, serotonin syndrome due to inappropriate psychiatric medication was diagnosed. The management of secondary psychiatric syndromes must be adapted to changes in the patient's primary condition, which necessitates interdisciplinary collaboration in general hospital settings.

Serotonin syndrome due to concomitant use of linezolid and methadone

Serotonin syndrome is a potentially life-threatening adverse drug reaction typically caused by a single or combination of two or more medications with serotonergic properties due to increased serotonin release. Our case is a 60-year-old drug-addict man who was admitted to the poisoning department of Loghman hospital with methadone poisoning. On the fifth day of hospitalization and after initiating the linezolid treatment for VAP, the patient began to run a fever with agitation, tremor, spontaneous clonus movement in the hands, and tachycardia. Due to patients' manifestations and after ruling out other diagnoses, serotonin syndrome was confirmed with the possibility of concomitant use of linezolid and methadone. Linezolid administration was promptly discontinued, and vancomycin therapy was initiated (1000 mg twice a day intravenously). Supportive therapies were performed. Finally, tremor, rigidity, and clonus movement disappeared within 48 h.

The promises and perils of psychedelic pharmacology for psychiatry

Psychedelic drugs including psilocybin, N,N'-dimethyltryptamine (DMT) and lysergic acid diethylamide (LSD) are undergoing a renaissance as potentially useful drugs for various neuropsychiatric diseases, with a rapid onset of therapeutic activity. Notably, phase II trials have shown that psilocybin can produce statistically significant clinical effects following one or two administrations in depression and anxiety. These findings have inspired a 'gold rush' of commercial interest, with nearly 60 companies already formed to explore opportunities for psychedelics in treating diverse diseases. Additionally, these remarkable phenomenological and clinical observations are informing hypotheses about potential molecular mechanisms of action that need elucidation to realize the full potential of this investigative space. In particular, despite compelling evidence that the 5-HT_2A receptor is a critical mediator of the behavioural effects of psychedelic drugs, uncertainty remains about which aspects of 5-HT_2A receptor activity in the central nervous system are responsible for therapeutic effects and to what degree they can be isolated by developing novel chemical probes with differing specificity and selectivity profiles. Here, we discuss this emerging area of therapeutics, covering both controversies and areas of consensus related to the opportunities and perils of psychedelic and psychedelic-inspired therapeutics. We highlight how basic science breakthroughs can guide the discovery and development of psychedelic-inspired medications with the potential for improved efficacy without hallucinogenic or rewarding actions.

The Omnipresence of Autonomic Modulation in Health and Disease

The Autonomic Nervous System (ANS) is a critical part of the homeostatic machinery with both central and peripheral components. However, little is known about the integration of these components and their joint role in the maintenance of health and in allostatic derailments leading to somatic and/or neuropsychiatric (co)morbidity. Based on a comprehensive literature search on the ANS neuroanatomy we dissect the complex integration of the ANS: (1) First we summarize Stress and Homeostatic Equilibrium - elucidating the responsivity of the ANS to stressors; (2) Second we describe the overall process of how the ANS is involved in Adaptation and Maladaptation to Stress; (3) In the third section the ANS is hierarchically partitioned into the peripheral/spinal, brainstem, subcortical and cortical components of the nervous system. We utilize this anatomical basis to define a model of autonomic integration. (4) Finally, we deploy the model to describe human ANS involvement in (a) Hypofunctional and (b) Hyperfunctional states providing examples in the healthy state and in clinical conditions.

Retrospective analysis of hops toxicosis in dogs (2002-2014): 71 cases

OBJECTIVE

To describe a population of dogs with hops toxicosis, including clinical signs observed, treatments performed, patient outcome, and overall prognosis. Clinical findings and treatment interventions were evaluated for their potential effects on outcome. This study also aims to review hops toxicosis and treatment options.

DESIGN

Retrospective observational study.

SETTING

Poison Control Center.

ANIMALS

Seventy-one dogs presenting for hops ingestion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Records of 71 dogs with known hops ingestion from the ASPCA - Animal Poison Control Center (ASPCA-APCC) database and the Tufts University medical record system were reviewed. Fifty-nine (77%) of the dogs survived. The most common clinical signs on presentation were hyperthermia and tachycardia, with presenting temperatures and heart rates significantly higher in nonsurvivors. There was no significant difference between survivors and nonsurvivors in regard to signalment. Time to presentation was shorter in survivors (5.0 vs 5.5 h; P < 0.0001). The median amount of hops ingested was higher in nonsurvivors (2 vs 2.5 oz; P < 0.0001). Hops ingestion caused hyperthermia in 96% (68/71) of dogs. The median time to death in the nonsurvivor group was 10.7 hours (2-30 h). None of the decontamination, cooling, or treatment measures (dantrolene, cyproheptadine, sedatives) evaluated in this population were associated with improved survival. After adjusting for cooling, time to presentation, and dantrolene administration, every degree of elevation in temperature was associated with a 78% increased chance of death. All dogs that survived to discharge had complete resolution of clinical signs.

CONCLUSIONS

Hops toxicosis can result in significant hyperthermia, tachypnea, and tachycardia. Seventy-seven percent of dogs survived with intensive treatment. Continued education of the potential for hops toxicosis is advised.

Fatal serotonin syndrome: a systematic review of 56 cases in the literature

INTRODUCTION

Serotonin syndrome (SS) is a drug-induced potentially life-threatening clinical condition. There is a paucity of data on the risk factors, clinical course, and complications associated with fatal SS.

OBJECTIVE

To characterize the epidemiological profile, clinical features, and risk factors associated with fatal SS through a systematic review.

METHODS

We performed a systematic review of MEDLINE and Google Scholar for case reports, case series, or cohort studies of fatal SS.

RESULTS

Initial database search identified 2326 articles of which 46 (56 patients) were included in the final analysis. The mean age was 42.3 years (range 18-87 years) with female predominance (57%). North America and Europe constitute 80% of the reported fatal SS. The symptoms evolved very rapidly, within 24 h after the administration of serotonergic drugs in 59% of the cases. Fever (61%) was the most common symptom, followed by seizure (36%) and tremors (30%). The mean temperature in the reported cases (25 patients) was 41.6 ± 1.3 °C (range 38.3-43.5 °C). SS was reported to occur with the maintenance dosage of serotonergic agents, after initiation of the drug for the first time, and addition of the drugs for the development of another unrelated illness. Creatine kinase (CK) activities were elevated (>3 times of the upper limit of normal) in eighteen patients, and it was very high (>25,000 IU/L) in four patients. Presence of high grade fever, seizures, and high CK activities may be associated with severe SS. Nine patients (16%) received 5-HT2A antagonists as a therapy. About 50% of patients died within 24 h of the onset of symptoms.

CONCLUSIONS

While fatal SS is rare, frequently observed features include hyperthermia, seizures, and high CK activities. Cyproheptadine use appears infrequent for these patients.

Life-Threatening Serotonin Syndrome Precipitated by Discontinuation of Serotonin-Dopamine Antagonist in the Presence of Serotonergic Agents: A Case Report

INTRODUCTION

Serotonin syndrome is caused by excessive activation of serotonin (5-hydroxytryptamine [5-HT]) neurotransmission. Although the discontinuation of antipsychotics with 5-HT2 receptor antagonistic characteristics could theoretically result in serotonin syndrome, there have been very few reports on the syndrome thus far.

CASE PRESENTATION

A 75-year-old woman with somatoform disorder was transferred to our emergency room because of pyrexia, unconsciousness, and myoclonus with hyperreflexia. She had been taking milnacipran and perospirone for 10 years and had started taking duloxetine 2 months before the event. Thereafter, she suffered diaphoresis, gait disturbance, and tremor. Her psychiatrist advised her to stop taking perospirone, because of suspicion of extrapyramidal symptoms, a day before admission. The clinical diagnosis of serotonin syndrome was made based on her symptoms while using serotonergic agents. Her symptoms were so severe that she was transferred to the intensive care unit, where supportive care was successful.

CONCLUSIONS

Discontinuation of antipsychotics that are 5-HT2 receptor antagonists may lead to serotonin syndrome in patients who take serotonergic agents. As extrapyramidal symptoms and serotonin toxicity share some clinical features, detailed drug history and physical examination are necessary for successful treatment.

Serotonin Syndrome: Pathophysiology, Clinical Features, Management, and Potential Future Directions

Serotonin syndrome (SS) (also referred to as serotonin toxicity) is a potentially life-threatening drug-induced toxidrome associated with increased serotonergic activity in both the peripheral (PNS) and central nervous systems (CNS). It is characterised by a dose-relevant spectrum of clinical findings related to the level of free serotonin (5-hydroxytryptamine [5-HT]), or 5-HT receptor activation (predominantly the 5-HT_1A and 5-HT_2A subtypes), which include neuromuscular abnormalities, autonomic hyperactivity, and mental state changes. Severe SS is only usually precipitated by the simultaneous initiation of 2 or more serotonergic drugs, but the syndrome can also occur after the initiation of a single serotonergic drug in a susceptible individual, the addition of a second or third agent to long-standing doses of a maintenance serotonergic drug, or after an overdose. The combination of a monoamine oxidase inhibitor (MAOI), in particular MAO-A inhibitors that preferentially inhibit the metabolism of 5-HT, with serotonergic drugs is especially dangerous, and may lead to the most severe form of the syndrome, and occasionally death. This review describes our current understanding of the pathophysiology, clinical presentation and management of SS, and summarises some of the drugs and interactions that may precipitate the condition. We also discuss the newer novel psychoactive substances (NPSs), a growing public health concern due to their increased availability and use, and their potential risk to evoke the syndrome. Finally, we discuss whether the inhibition of tryptophan hydroxylase (TPH), in particular the neuronal isoform (TPH2), may provide an opportunity to pharmacologically target central 5-HT synthesis, and so develop new treatments for severe, life-threatening SS.

Focal seizure as a manifestation of serotonin syndrome: case report

Serotonin syndrome is a life-threatening condition. Seizure is one of the complications of serotonin syndrome that may delay diagnosis and complicate management. We report a patient who had a focal seizure with abnormal electroencephalogram in the setting of serotonin syndrome with no prior history of epilepsy or seizure-provoking factors (fever, electrolyte abnormalities, specific medication combinations, and specific medication overdosing). Recognition of seizure as a symptom of serotonin syndrome is important for early treatment and avoidance of long-term consequences. Treatment of serotonin syndrome is mostly supportive. However, a short course of antiepileptics may be needed if these patients develop seizures.

The Serotonin Syndrome: From Molecular Mechanisms to Clinical Practice

The serotonin syndrome is a medication-induced condition resulting from serotonergic hyperactivity, usually involving antidepressant medications. As the number of patients experiencing medically-treated major depressive disorder increases, so does the population at risk for experiencing serotonin syndrome. Excessive synaptic stimulation of 5-HT_2A receptors results in autonomic and neuromuscular aberrations with potentially life-threatening consequences. In this review, we will outline the molecular basis of the disease and describe how pharmacologic agents that are in common clinical use can interfere with normal serotonergic pathways to result in a potentially fatal outcome. Given that serotonin syndrome can imitate other clinical conditions, an understanding of the molecular context of this condition is essential for its detection and in order to prevent rapid clinical deterioration.

Management of severe arterial hypertension associated with serotonin syndrome: a case report analysis based on systematic review techniques

Serotonin syndrome is thought to arise from serotonin excess. In many cases, symptoms are mild and self-limiting. But serotonin syndrome can become life threatening, when neuromuscular hyperexcitability spins out of control. Uncontainable neuromuscular hyperexcitability may lead to cardiovascular complications, linked to extreme changes in blood pressure. Currently, there is little guidance on how to control blood pressure in hyperserotonergic states. We report a case with treatment-resistant arterial hypertension, followed by a clinical review (using systematic review principles and techniques) of the available evidence from case reports published between 2004 and 2016 to identify measures to control arterial hypertension associated with serotonin syndrome. We conclude that classic antihypertensives may not be effective for the treatment of severe hypertension associated with serotonin syndrome. Benzodiazepines may lower blood pressure. Patients with severe hypertension not responding to benzodiazepines may benefit from cyproheptadine, propofol or both. In severe cases, higher cyproheptadine doses than currently recommended may be necessary.

Neuroleptic malignant syndrome as part of an akinetic crisis associated with sepsis in a patient with Lewy body disease

A 65-year-old Japanese woman with Parkinson's disease, later diagnosed with Lewy body disease, presented with a 2-day history of systemic tremors. She also had fever without rigidity or creatine kinase (CK) elevation. She was diagnosed with sepsis caused by pyelonephritis with acute kidney injury and parkinsonism exacerbation. Although antibiotic and fluid therapy improved her pyuria and renal function, her fever and tremors persisted. On the fourth day, her symptoms worsened and resulted in cardiopulmonary arrest; however, quick resuscitation allowed the return of spontaneous circulation. Simultaneously, hyperthermia, altered consciousness, extrapyramidal symptoms, dysautonomia and CK elevation were noted. Thus, dantrolene administration was initiated with a tentative diagnosis of neuroleptic malignant syndrome (NMS). This caused her fever to subside, and her symptoms gradually improved. It was difficult to distinguish between parkinsonism exacerbation associated with sepsis and NMS. Physicians should consider NMS early on, even if the patient does not fulfil the diagnostic criteria.

Serotonin Syndrome and the Anaesthetist

Serotonin syndrome results from excessive activation of serotonin (5-hydroxytryptamine; 5-HT) receptors in the nervous system, on the surface of platelets, and on the vascular endothelium. The clinical manifestations are a triad of altered conscious state, autonomic dysfunction, and neuromuscular excitability. Clinical diagnostic criteria remain poorly defined and unvalidated, and there are no available investigations to confirm the diagnosis. The syndrome is caused by the administration of one or more drugs possessing serotonergic activity. Severe forms of the syndrome usually result from overdose, but can be induced by monotherapy. The exact incidence of serotonin syndrome remains unknown, but is likely to be increasing due to increased prescription of selective serotonin reuptake inhibitor anti-depressants and tramadol, as well as recreational use of amphetamine-like substances. Serotonin syndrome may complicate the administration of drugs frequently used in anaesthetic practice, including pethidine and tramadol. Although the majority of cases improve with symptomatic and supportive care, severe cases need intensive care and frequently require mechanical ventilation. Neuromuscular excitability is likely to be the cause of rhabdomyolysis seen in severe cases and should be treated with benzodiazepines and muscle relaxants. Supportive therapies are required to treat hyperthermia and autonomic dysfunction. Cyproheptadine is the most commonly administered serotonergic antagonist, but is unavailable in parenteral form.

Association Between Serotonin Syndrome and Second-Generation Antipsychotics via Pharmacological Target-Adverse Event Analysis

Case reports suggest an association between second‐generation antipsychotics (SGAs) and serotonin syndrome (SS). The US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) was analyzed to generate hypotheses about how SGAs may interact with pharmacological targets associated with SS. FAERS was integrated with additional sources to link information about adverse events with drugs and targets. Using Proportional Reporting Ratios, we identified signals that were further investigated with the literature to evaluate mechanistic hypotheses formed from the integrated FAERS data. Analysis revealed common pharmacological targets perturbed in both SGA and SS cases, indicating that SGAs may induce SS. The literature also supported 5‐HT_2A antagonism and 5‐HT_1A agonism as common mechanisms that may explain the SGA‐SS association. Additionally, integrated FAERS data mining and case studies suggest that interactions between SGAs and other serotonergic agents may increase the risk for SS. Computational analysis can provide additional insights into the mechanisms underlying the relationship between SGAs and SS.

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.

Toxicologic Emergencies in Patients with Mental Illness: When Medications Are No Longer Your Friends

Patients with psychiatric disorders are at risk for toxicologic emergencies. Psychotropic medications have numerous effects on the neurologic, cardiac, and other organ systems and interact with other medications, potentially leading to further side effects. It is important to become familiar with accepted psychiatric practice guidelines, common toxidromes, medical sequelae associated with prescribed medications, and the specific workup and treatment of overdoses of frequently prescribed psychotropics.

Dietary Supplement-Drug Interaction-Induced Serotonin Syndrome Progressing to Acute Compartment Syndrome

BACKGROUND Dietary supplements have been associated with an increase in emergency intervention as a result of unexpected adverse events. Limited resources and information on significant drug-drug interactions with dietary supplements and prescription medications have contributed to associated complications and unexpected events. We present the case of a patient who consumed multiple prescription medications and dietary supplements which resulted in significant complications. CASE REPORT A 28-year-old man presented to the Emergency Department complaining of severe calf pain after exercising. In addition to his prescription medications, which included sertraline, he also consumed dietary supplements prior to his workout. He developed serotonin syndrome with rhabdomyolysis, which rapidly progressed to acute compartment syndrome. An emergency bilateral four-compartment double-incision lower extremity and forearm fasciotomy was performed, with complete recovery. CONCLUSIONS Drug-drug interactions involving dietary supplements are frequently overlooked in most healthcare settings, especially in the Emergency Department. Health care providers should be cognizant of the potential drug- drug interactions resulting in serotonin syndrome to prevent the progression to acute compartment syndrome and associated complications. Pharmacists play a key role in recognizing drug-dietary supplement interactions and adverse effects.

Rare case of severe serotonin syndrome leading to bilateral compartment syndrome

The term 'serotonin syndrome' describes a constellation of symptoms caused by serotonergic overstimulation. Its characteristic clinical presentation consists of encephalopathy, neuromuscular signs and autonomic hyperactivity. After removal of the offending agent, the clinical course is usually self-limited but can occasionally lead to severe symptoms. We report the case of a 68-year-old woman who presented emergently with encephalopathy. Home medications included paroxetine and dextroamphetamine/amphetamine. Physical examination revealed tachycardia, tachypnoea, diaphoresis, rigidity, hyperreflexia and clonus. Given the fast onset of symptoms, a diagnosis of serotonin syndrome was made. Laboratory studies showed acute-on-chronic kidney injury and elevated creatine kinase. The patient's mental status quickly returned to baseline with supportive care. Her rhabdomyolysis, however, persisted and led to acute compartment syndrome in her lower extremities. After bilateral leg fasciotomies and treatment of a severe wound infection with intravenous antibiotics, the patient has now recovered with complete resolution of her symptoms.

Metoclopramide-induced Serotonin Syndrome

A 40-year-old woman with bipolar disorder who was taking mirtazapine presented with mydriasis, abnormal diaphoresis, myoclonus and muscle rigidity after taking metocloplamide. Her medical history, which included the use of serotonergic agents, and the presence of symptoms including myoclonus and muscle rigidity were consistent with a diagnosis of serotonin syndrome (SS) according to the Hunter criteria. The symptoms diminished following three days of treatment with oral lorazepam and cyproheptadine and a reduced dose of mirtazapine. Metoclopramide is frequently used to various gastric symptom. Metoclopramide is not widely known to induce SS. This potentially fatal condition should be avoided by exercising care in the use of drugs that have the potential to cause drug-drug interactions.

A Case Report of Probable Paliperidone ER-Induced Serotonin Syndrome in a 17-Year-Old Taiwanese Female With New Onset Psychosis

A 17-year-old female with new-onset psychosis was treated with paliperidone. After increasing the paliperidone dose to 12 mg per day the patient developed a series of side effects; Tachycardia (140 bpm), severe drooling, restlessness, diaphoresis, whole-body tremor, inducible foot clonus, predominant lower limbs rigidity, bilateral pupil dilation, increased bowel sounds with watery diarrhea, and muscle hypertonicity. The symptoms subsided after stopping the paliperidone, and recurred after resuming paliperidone 9 mg per day. To our knowledge, this is the first case of a very clear and close relationship between the symptoms of serotonin syndrome and the use of paliperidone. We have to cautiously consider the diagnosis of serotonin syndrome in potential cases.

Serotonin Syndrome in the Setting of Lamotrigine, Aripiprazole, and Cocaine Use

Serotonin syndrome is a potentially life-threatening condition associated with increased serotonergic activity in the central nervous system. It is classically associated with the simultaneous administration of two serotonergic agents, but it can occur after initiation of a single serotonergic drug or increasing the dose of a serotonergic drug in individuals who are particularly sensitive to serotonin. We describe a case of serotonin syndrome that occurred after ingestion of higher than prescribed doses of lamotrigine and aripiprazole, in addition to cocaine abuse. The diagnosis was established based on Hunter toxicity criteria and severity was classified as mild. The features of this syndrome resolved shortly after discontinuation of the offending agents. Serotonin syndrome is characterized by mental status changes, autonomic hyperactivity, and neuromuscular abnormalities along a spectrum ranging from mild to severe. Serotonin syndrome in our patient was most likely caused by the pharmacokinetic and pharmacodynamic interactions between lamotrigine, aripiprazole, and cocaine leading to increased CNS serotonergic activity.

Neuroleptic Malignant Syndrome: A Case Aimed at Raising Clinical Awareness

A 60-year-old man with a history of bipolar disorder on risperidone, bupropion, and escitalopram was admitted for community acquired streptococcal pneumonia. Four days later, he developed persistent hyperthermia, dysautonomia, rigidity, hyporeflexia, and marked elevation of serum creatine phosphokinase. He was diagnosed with neuroleptic malignant syndrome (NMS) and improved with dantrolene, bromocriptine, and supportive therapy. This case emphasizes the importance of considering a broad differential diagnosis for fever in the ICU, carefully reviewing the medication list for all patients, and considering NMS in patients with fever and rigidity.

Serotonin syndrome after sertraline overdose in a child: a case report

Serotonin syndrome is a potentially life-threatening drug effect. It may be misdiagnosed because it has mostly been reported in adults. Case Report. An 8-year-old girl with behavioral problems and medicated with risperidone and sertraline was admitted in the emergency department after she had taken voluntarily 1500 mg of sertraline (50 mg/kg). At admission, she had marked agitation, visual hallucinations, diaphoresis, flushing, and tremor. She had fever and periods of hypertension. She also showed generalized rigidity and involuntary movements. She was treated with fluids and iv diazepam, midazolam, clemastine, and biperiden. As the patient presented a severe insomnia and a progressive rhabdomyolysis, she was transferred to pediatric intensive care unit (ICU), where she was under treatment with cyproheptadine, mechanical ventilation, and muscular paralysis for 11 days. She was discharged from hospital a few days later with no neurological sequelae. Conclusions. Serotonin syndrome is still not well recognized by physicians. In our patient, the diagnosis was made early due to the history of overdose with serotonin reuptake inhibitors and the triad of mental, neurological, and autonomic signs. Parents must be educated to prevent children from having free access to drugs, avoiding self-medication or overdose.

Case reports of neuroleptic malignant syndrome in context of quetiapine use

A retrospective analysis was followed on 20 case reports covering the possible correlation between the atypical antipsychotic, quetiapine, and neuroleptic malignant syndrome (NMS), determined by the study of 7 different NMS criteria guidelines. A great majority (19) of the case studies did not meet the requirements of all 7 guidelines, frequently due to unreported information. Nor was quetiapine proven to be the sole cause of the possible NMS in the two age groups investigated. Only one case was found to have no other medication or medical conditions confounding the relationship of quetiapine and NMS symptoms, and that case was in the context of a significant quetiapine overdose. The other 19 cases demonstrated the difficulty of identifying the cause of NMS when polypharmacy and other medical conditions are involved. The authors note the need for caution in deciding both the presence of NMS and the causal factors of the symptoms.

Serotonin syndrome: is it a reason to avoid the use of tramadol with antidepressants?

BACKGROUND

There is a warning associated with all serotonergic antidepressants and its concomitant use with tramadol due to the concern for a drug-drug interaction resulting in serotonin syndrome (SS). The prescribing of antidepressants with tramadol may be unnecessarily restricted due to fear of causing this syndrome.

OBJECTIVES

There are 3 objectives of this review. To (1) review case reports of SS associated with the combination of tramadol and antidepressant drugs in recommended doses, (2) describe the mechanisms of the drug interaction, and (3) identify the potential risk factors for SS.

METHODS

Case reports of SS associated with tramadol and antidepressants were identified via Cochrane Library, PubMed, and Ovid (through October 2012) using search terms SS, tramadol, antidepressants, fluoxetine, sertraline, paroxetine, fluvoxamine, citalopram, escitalopram, venlafaxine, desvenlafaxine, duloxetine, mirtazapine, milnacipran, trazodone, vilazodone, and bupropion. Cases involving monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants were excluded.

RESULTS

Nine articles were identified describing 10 cases of suspected SS associated with therapeutic doses of tramadol combined with an antidepressant. Mechanisms of the drug-drug interactions involve pharmacodynamic, pharmacokinetic, and possible pharmacogenetic factors.

CONCLUSIONS

Review of the available case reports of tramadol combined with antidepressant drugs in therapeutic doses indicates caution in regard to the potential for SS but does not constitute a contraindication to their use. Tramadol is only contraindicated in combination with MAOIs but not other antidepressants in common use today. These case reports do suggest several factors associated with a greater risk of SS, including increased age, higher dosages, and use of concomitant potent cytochrome P450 2D6 inhibitors. Tramadol can be safely combined with antidepressants; however, monitoring and counseling patients are prudent when starting a new serotonergic agent or when doses are increased.

Diagnosis and treatment of drug-induced hyperthermia

PURPOSE

The etiology, pathophysiology, clinical presentation, and management of drug-induced hyperthermia (DIH) syndromes are reviewed.

SUMMARY

DIH syndromes are a rare and often overlooked cause of body temperature elevation and can be fatal if not recognized promptly and managed appropriately. There are five major DIH syndromes: (1) neuroleptic malignant syndrome, (2) serotonin syndrome, (3) anticholinergic poisoning, (4) sympathomimetic poisoning, and (5) malignant hyperthermia. The differential diagnosis of DIH syndromes can be challenging because symptoms are generally nonspecific, ranging from blood pressure changes and excessive sweating to altered mental status, muscle rigidity, convulsions, and metabolic acidosis. Evidence from the professional literature (per a MEDLINE search for articles published through November 2011) indicates that few currently available treatment options can reduce the duration of hyperthermia; therefore, prompt identification of the provoking agent based on the patient's medication history, the clinical presentation, and the timing of symptom onset is essential to determine the appropriate treatment and mitigate potentially life-threatening sequelae. For all DIH syndromes, appropriate management includes the immediate discontinuation of the suspected offending agent(s) and supportive care (external cooling, volume resuscitation as needed); in some cases, pharmacologic therapy (e.g., a benzodiazepine, bromocriptine, dantrolene) may be appropriate, with the selection of a specific agent primarily determined by the medication history and suspected DIH syndrome.

CONCLUSION

DIH is a hypermetabolic state caused by medications and other agents that alter neurotransmitter levels. The treatment of DIH syndromes includes supportive care and pharmacotherapy as appropriate.

Selective serotonin reuptake inhibitor (SSRI) toxicosis in cats: 33 cases (2004-2010)

OBJECTIVE

To evaluate a population of cats with selective-serotonin reuptake inhibitor (SSRI) toxicosis and characterize the population affected, list products ingested, the clinical signs observed, treatments performed, length of hospitalization, patient outcome, and overall prognosis.

DESIGN

Retrospective study from 2004 to 2010.

SETTING

Referral veterinary center.

ANIMALS

Thirty-three witnessed cat SSRI ingestions.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The medical records of cats with a witnessed SSRI ingestion identified by review of an animal poison control center electronic database were evaluated. The most common SSRIs ingested were venlafaxine (Effexor; 12/33; 36%), fluoxetine (Prozac; 12/33; 36%), citalopram (Celexa; 6/33; 18%), and escitalopram (Lexapro; 3/33; 9%). Overall, 24% of cats (8/33) became symptomatic, while 76% (25/33) remained asymptomatic. Of the symptomatic cats, sedation was the most common clinical sign (6/8; 75%), followed by gastrointestinal signs (4/8; 50%), central nervous system stimulation (1/8; 13%), cardiovascular signs (1/8; 13%), and hyperthermia (1/8; 13%). Veterinary care was sought in 20 cats (20/33; 61%). Sixteen cats (16/20; 80%) were hospitalized, while 4 cats (4/20; 20%) were treated as outpatients. Treatment for hospitalized patients included administration of IV fluid therapy (14/16; 88%), activated charcoal (12/16; 75%), anti-arrhythmic agents (7/16; 44%), methocarbamol (6/16; 38%), cyproheptadine (6/16; 38%), anti-emetics (5/16; 31%), and sedation (5/16; 31%). Diagnostics included blood work (7/16; 44%), blood pressure measurement (3/16; 19%), and electrocardiogram monitoring (2/16; 13%). Mean hospitalization time for all cases of SSRI ingestion was 14.6 ± 7.8 hours (n = 16). All symptomatic cats in this study (8/8; 100%) had resolution of clinical signs and survived to discharge.

CONCLUSIONS

The prognosis for SSRI ingestion in this population of cats was excellent. Decontamination and supportive care for at least 12-24 hours can be considered in cats with SSRI ingestion, particularly venlafaxine to monitor resolution of clinical signs.