Concomitant treatment with safinamide and antidepressant drugs: Safety data from real clinical practice

BACKGROUND AND PURPOSE

The aim of this study was to assess the possible pharmacological interactions between safinamide and antidepressants, and in particular the appearance of serotonin syndrome with data from real life.

METHODS

We conducted a retrospective observational study of patients with Parkinson's disease from our Movement Disorders Unit, who were under treatment with any antidepressant drug and safinamide. Specifically, symptoms suggestive of serotonin syndrome were screened for. Also, we collected time of simultaneous use, doses of levodopa and other antiparkinsonian drugs.

RESULTS

Clinical records were reviewed for the study period of September 2018 to September 2019. Seventy-eight PD patients who were treated with safinamide of which 25 (32.05%) had a concomitant treatment with an antidepressant drug, being sertraline and escitalopram the most frequent. Mean age was 80 years±8.43 and H&Y stage was 3 [2-4]. Mean dose of levodopa used was 703.75mg±233.15. Median duration of concomitant treatment with safinamide and antidepressant drug was 6 months (IQR 20.5), and over eighteen months in 5 cases. No case of serotonin syndrome was recorded, neither was any of its typical manifestations combined or in isolation.

CONCLUSIONS

Our real clinical practice study suggests that concomitant use of safinamide with antidepressant drugs in PD patients seemed to be safe and well tolerated, even in the long term. However, caution is warranted, individualizing treatment regimens and monitoring the potential appearance of adverse effects.

[Retrospective analysis of venlafaxine-induced hypoglycemia in patients with overdose]

INTRODUCTION

Recent publications relate the presence of hypoglycemia in venlafaxine (VLX) poisoning depending on the dose. Our aim was to analyze the clinical characteristics of patients who presented hypoglycemia induced by VLF overdose.

PATIENTS AND METHODS

Retrospective study carried out in the Balearic Islands (2020-2023).

INCLUSION CRITERIA

serum concentrations of VLX + O-desmethyl-venlafaxine (O-VLX)>800 ng/mL. The characteristics of patients with and without hypoglycemia were compared.

RESULTS

Twenty-one patients were included, 8 (38.1%) with hypoglycemia. No differences were found in the doses referred to in both groups. Peak concentrations of VLX + O-VLX (ng/mL) were 9,783 [4,459-17,976] in patients with hypoglycemia and 1,413 [930-1,719] in patients without hypoglycemia (p<0.0001). The presence of hypoglycemia was associated with: lower age and level of consciousness; and higher frequency of suicide attempts, seizures, mydriasis, tachycardia and serotonin syndrome, invasive respiratory support, fluid therapy and ICU admission (p<0.05).

CONCLUSIONS

The detection of hypoglycemia in a VLX overdose case is a readily available marker to suspect the severity of the patient. In any case, serum concentrations when available allow us to confirm intoxication.

Potential Dextromethorphan-Induced Serotonin Syndrome Leading to Homicide and Suicide

Limited case reports have been published regarding serotonin syndrome due to the combined effects of supratherapeutic levels of dextromethorphan and selective serotonin reuptake inhibitor. We report a case of an adolescent with postmortem findings suggestive of a diagnosis of serotonin syndrome-induced psychosis associated with a double homicide and suicide. Postmortem toxicology of the suicide victim was remarkable for elevated serotonergic metabolites of fluoxetine and dextromethorphan in a 14-year-old male.

Serotonin syndrome: A pharmacovigilance comparative study of drugs affecting serotonin levels

BACKGROUND

Serotonin syndrome is a rare and potentially fatal adverse drug reaction caused by serotonergic drugs and is due to an increase in serotonin concentration or activation of the 5-HT receptor in the central nervous system. We analysed adverse events in the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) data set to investigate the main drug classes related to reports of serotonin syndrome and the reporting risk in relation to age and sex.

METHODS

We analysed data from the FAERS database to evaluate the main drug classes related to reports of the serotonin syndrome, and the reporting risk in relation to age and sex.

RESULTS

We found 8,997 cases of serotonin syndrome; selective serotonin reuptake inhibitors (SSRIs) was the class of drugs with most reports, followed by opioids and other antidepressants. The highest Reporting Odds Ratios (ROR) for drug classes was for monoamine oxidase (MAO) inhibitors (45.99, 95% confidence interval (CI): 41.21-51.33) and SSRIs (32.66, 95% CI: 31.33-34.04), while the ten active substances with the highest ROR were moclobemide, isocarboxazid, oxitriptane, tranylcypromine, melitracen, phenelzine, linezolid, amoxapine, reboxetine and tryptophan; with values of ROR ranging from 44.19 (95% CI: 25.38-76.94) of tryptophan to 388.36 (95% CI: 314.58-479.46) of moclobemide. The ROR for the most commonly involved drugs was higher in the group of older adults (65 > years old), and higher in males.

CONCLUSION

Prescribers need to be vigilant about drugs that can raise serotonin concentration or influence serotonergic neurotransmission, also when using drugs with less well-known risk for serotonin syndrome, like linezolid and triptans.

A suspected case of serotonin syndrome induced by palonosetron and ramosetron administration

Serotonin syndrome occurs when serotonin (5-hydroxytryptamine, 5-HT) levels increase and is accompanied by symptoms of mental status changes, neuromuscular abnormalities, and autonomic hyperactivity. Serotonin receptor 3 antagonists, such as palonosetron or ramosetron, are commonly used for their antiemetic effects during general anesthesia. However, overdosage of these drugs carries a risk of serotonergic toxicity as they increase serum serotonin levels due to inhibition of serotonin reuptake. Serotonin syndrome caused by 5-HT3 antagonists is thought to be caused by the synergistic effects of high doses of serotonergic drugs or the combination of two or more serotonergic drugs with different mechanisms of action. The incidence of serotonin syndrome is unknown because it is a rare condition that cannot be selected for in randomized clinical trials. Therefore, physicians must focus on the clinical manifestations of the syndrome and manage patients before the condition becomes life-threatening.

Serotonin Syndrome Precipitated by Amantadine in a Patient With Persistent Post Concussive Symptoms - A Case Report

Symptoms after mild traumatic brain injury (MTBI) can persist for greater than 1 month in up to 20% of individuals, yet there are no current medications approved by the Food and Drug Administration for treatment of specific concussion related sequelae. Amantadine, a dopamine agonist and N-Methyl-D-aspartate antagonist, is increasingly being used as a treatment option for individuals with traumatic brain injury across the spectrum of injury severity. This case report describes a 22-year-old individual who sustained an MTBI without loss of consciousness or post-traumatic amnesia after striking their head against a metal cabinet. The individual was referred to an interdisciplinary outpatient brain rehabilitation program secondary to persistent symptoms after MTBI, was prescribed amantadine for post-traumatic headache 97 days after injury, and subsequently developed symptoms of serotonin syndrome (SS) within 10 days of medication initiation. While SS caused by amantadine has been described in individuals with renal failure, this case report is the first to describe amantadine precipitating SS - confirmed by a validated diagnostic criterion and successfully treated with lorazepam and cyproheptadine - in a patient with normal renal function already on duloxetine, bupropion, and gabapentin. This case report is important in elucidating potential contributions of amantadine to the development of SS and highlighting the important role clinicians have in assessing for polypharmacy when prescribing amantadine for individuals with traumatic and acquired brain injuries.

A clinical review of antidepressants, their sexual side-effects, post-SSRI sexual dysfunction, and serotonin syndrome

Depression and anxiety are common, with one in six people experiencing symptoms in any given week. Of these people, 8.32 million are prescribed antidepressants. People living with HIV are likely to experience psychiatric disorder, with one in three experiencing depression and anxiety, and being at greater risk of developing post-traumatic stress disorder. Sexual side-effects of psychotropic medication are very common, cause distress, and can persist even after the medication has been withdrawn. Antidepressants are powerful drugs and can have severe interactions with many other substances. This article seeks to raise awareness of sexual side-effects of psychotropic medications and draw attention to ethical issues related to post selective serotonin reuptake inhibitor sexual dysfunction (PSSD). Additional risk factors and interactions between psychotropic medications and recreational drugs are identified. Recommendations are made to improve care and clinical outcomes through the development of therapeutic alliances.

Serotonin Syndrome

BACKGROUND

Serotonin syndrome is a potentially life-threatening syndrome with manifestations spanning from mild adverse effects to life-threatening toxicity. The syndrome is caused by overstimulation of serotonin receptors by serotonergic drugs. Since the use of serotonergic drugs is increasing, primarily due to the widespread use of selective serotonin reuptake inhibitors, cases of serotonin syndrome have likely seen a parallel increase. The true incidence of serotonin syndrome remains unknown due to its diffuse clinical presentation.

OBJECTIVES

This review aims to provide a clinically focused overview of serotonin syndrome, covering its pathophysiology, epidemiology, clinical manifestations, diagnostic criteria, differential diagnosis, and treatment as well as classifying serotonergic drugs and their mechanism of action. The pharmacological context is emphasized, as it is crucial for detection and management of serotonin syndrome.

METHODS

Focused review based on a literature search using the PubMed database.

FINDINGS AND CONCLUSION

Serotonin syndrome can occur through therapeutic use or overdose of a single serotonergic drug, or as a drug interaction between two or more serotonergic drugs. Central clinical features consist of neuromuscular excitation, autonomic dysfunction and altered mental status, occurring in a patient undergoing new or altered serotonergic therapy. Early clinically recognition and treatment are crucial to prevent significant morbidity.

Non-Psychosis Symptoms of Clozapine Withdrawal: a Systematic Review

OBJECTIVE

Clozapine is a potent antipsychotic medication with a complex receptor profile. It is reserved for treatment-resistant schizophrenia. We systematically reviewed studies of non-psychosis symptoms of clozapine withdrawal.

METHODS

CINAHL, Medline, PsycINFO, PubMed, and the Cochrane Database of Systematic Reviews were searched using the keywords 'clozapine,' and 'withdrawal,' or 'supersensitivity,' 'cessation,' 'rebound,' or 'discontinuation'. Studies related to non-psychosis symptoms after clozapine withdrawal were included.

RESULTS

Five original studies and 63 case reports / series were included in analysis. In 195 patients included in the five original studies, approximately 20% experienced non-psychosis symptoms following discontinuation of clozapine. In 89 patients in four of the studies, 27 experienced cholinergic rebound, 13 exhibited extrapyramidal symptoms (including tardive dyskinesia), and three had catatonia. In 63 case reports / series included, 72 patients with non-psychosis symptoms were reported, which were catatonia (n=30), dystonia or dyskinesia (n=17), cholinergic rebound (n=11), serotonin syndrome (n=4), mania (n=3), insomnia (n=3), neuroleptic malignant syndrome (NMS) [n=3, one of them had both catatonia and NMS], and de novo obsessive compulsive symptoms (n=2). Restarting clozapine appeared to be the most effective treatment.

CONCLUSIONS

Non-psychosis symptoms following clozapine withdrawal have important clinical implications. Clinicians should be aware of the possible presentations of symptoms to ensure early recognition and management. Further research is warranted to better characterise the prevalence, risk factors, prognosis, and optimal drug dosing for each withdrawal symptom.

Linezolid-associated serotonin toxicity: a systematic review

PURPOSE

This systematic review aims to evaluate the existing evidence associating linezolid to serotonin toxicity when used as monotherapy or when co-administered with other serotonergic agents.

METHODS

A systematic literature search using PubMed (till March 2023), IDWeek meetings (2003-2023), the European Congress of Clinical Microbiology and Infectious Disease Annual Meetings (2001-2023), and the American College of Clinical Pharmacy (1999-2023) identified studies and abstracts related to linezolid and serotonin toxicity.

RESULTS

A total of 84 studies were included. The data collected in retrospective/observational studies compared the incidence of serotonin toxicity with linezolid monotherapy at 0.0050% and linezolid combination therapy at 0.0134%. All cases which discontinued linezolid and serotonergic agent/s at signs and symptoms of toxicity found symptom resolution; 75% of cases reported serotonin toxicity resolution within 24-48 h after discontinuation.

CONCLUSION

Linezolid therapy when optimal should not be deferred due to the risk of serotonin syndrome. The data collected reveals a low prevalence of serotonin toxicity in both linezolid monotherapy and linezolid concurrent with other serotonergic agents.

Intravenous dantrolene in hypermetabolic syndromes: a survey of the U.S. Veterans Health Administration database

BACKGROUND

Intravenous dantrolene is often prescribed for hypermetabolic syndromes other than the approved indication of malignant hyperthermia (MH). To clarify the extent of and indications for dantrolene use in conditions other than MH, we sought to document current practices in the frequency, diagnoses, clinical characteristics and outcomes associated with dantrolene treatment in critical care settings.

METHODS

Inpatients receiving intravenous dantrolene from October 1, 2004 to September 30, 2014 were identified retrospectively in the U.S. Veterans Health Administration national database. Extracted data included; diagnoses of hypermetabolic syndromes; triggering drugs; dantrolene dosages; demographics; vital signs; laboratory values; in-hospital mortality; complications; and lengths of stay. Frequency and mortality of patients who did not receive dantrolene were obtained in selected diagnoses for exploratory comparisons.

RESULTS

Dantrolene was administered to 304 inpatients. The most frequent diagnoses associated with dantrolene treatment were neuroleptic malignant syndrome (NMS; N = 108, 35.53%) and sepsis (N = 47, 15.46%), with MH accounting for only 13 (4.28%) cases. Over half the patients had psychiatric comorbidities and received psychotropic drugs before dantrolene treatment. Common clinical findings in patients receiving dantrolene included elevated temperature (mean ± SD; 38.7 ± 1.3 °C), pulse (116.33 ± 22.80/bpm), respirations (27.75 ± 9.58/min), creatine kinase levels (2,859.37 ± 6,646.88 IU/L) and low pO₂ (74.93 ± 40.16 mmHg). Respiratory, renal or cardiac failure were common complications. Mortality rates in-hospital were 24.01% overall, 7.69% in MH, 20.37% in NMS and 42.55% in sepsis, compared with mortality rates in larger and possibly less severe groups of unmatched patients with MH (5.26%), NMS (6.66%), or sepsis (41.91%) who did not receive dantrolene.

CONCLUSIONS

In over 95% of cases, dantrolene administration was associated with diagnoses other than MH in critically-ill patients with hypermetabolic symptoms and medical and psychiatric comorbidities. Exploratory survey data suggested that the efficacy and safety of dantrolene in preventing mortality in hypermetabolic syndromes other than MH remain uncertain. However, randomized and controlled studies using standardized criteria between groups matched for severity are essential to guide practice in using dantrolene.

Recreational drug toxicity with severe hyperthermia: Rapid onsite treatment and clinical course

Electronic dance music festivals have gained notoriety in the critical care and emergency medicine fields due to an alarming incidence of hospitalizations and deaths related to the high prevalence of recreational drug use. Recreational drug use toxicity, in part related to sympathomimetic toxidromes, may cause hyponatremia, seizures, rhabdomyolysis, hyperkalemia, acidosis, coagulopathy, circulatory shock, multi-organ failure, and even death. This wide-ranging syndrome has been referred to as psychostimulant drug-induced toxicity. Rapid onsite diagnosis and treatment, with attention to the A-B-C's of clinical emergencies, is essential to preserve life. We describe a patient presenting with the highest recorded core temperature in a survivor of psychostimulant drug-induced toxicity, and emphasize management principles of this life-threatening and increasingly prevalent condition.

High risk and low prevalence diseases: Serotonin syndrome

INTRODUCTION

Serotonin syndrome is a rare, frequently misdiagnosed, serious condition with high morbidity.

OBJECTIVE

This review highlights the pearls and pitfalls of serotonin syndrome, including diagnosis, initial resuscitation, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Serotonin syndrome is a potentially deadly toxidrome marked by excess serotonin receptor activity or neurotransmission. Features of serotonin syndrome include 1) neuromuscular excitation such as tremor, hyperreflexia, and clonus; 2) autonomic dysfunction such as tachycardia, hypertension/hypotension, and hyperthermia; and 3) altered mental status such as agitation, delirium, and coma. Although serotonin syndrome may be more obvious in patients who have overdosed on serotonergic agents such as serotonin reuptake inhibitors (SSRIs), multiple other medications may also cause serotonin syndrome. Alternative diagnoses such as sepsis, neuroleptic malignant syndrome, and decompensated hyperthyroidism should be considered. The primary components of therapy include stopping the offending agent and supportive care, which focuses on agitation control, monitoring for and treating hyperthermia, and managing autonomic instability.

CONCLUSIONS

An understanding of serotonin syndrome can assist emergency clinicians in diagnosing and managing this disease.

Drug-induced hyperthermia with rhabdomyolysis in CLN3 disease

CLN3 disease (MIM# 204200), the most prevalent of the neuronal ceroid lipofuscinoses (NCL), is an autosomal recessive disorder with juvenile onset characterized by blindness, epilepsy, dementia, psychiatric manifestations, and motor deterioration. Problems related to behavior, emotions and thought are among the main features. Antidepressant and antipsychotic drugs have been employed with variable results. Neuroleptic malignant syndrome (NMS) has previously been described in two patients with NCL, one with CLN3 disease and one with adult onset NCL of unclear genetic origin. Our aims were to describe the occurrence of drug-induced hyperthermia in pediatric patients with CLN3 disease from West and South Sweden and to delineate the range of associated clinical features. Our study identified four patients presenting with seven episodes of severe drug-induced hyperthermia and either NMS-like or Serotonin syndrome (SS)-like features. Possibly provoking drugs were risperidone, clozapine, olanzapine, haloperidol, quetiapine, and sertraline. The course was atypical, frequently prolonged, associated with rhabdomyolysis and status dystonicus, and resulted in the death of three of the patients. Our study points to a vulnerability to drug-induced hyperthermia in patients with CLN3 disease which we believe could be underreported. Interestingly the proposed pathophysiological mechanisms behind NMS and SS on one hand and CLN3 on the other hand seem to converge in a common mechanism involving dysregulation of the sympathetic nervous system.

Serotonin toxicity of serotonergic psychedelics

RATIONALE

In recent years, psychedelic substances with serotonergic mechanisms have accumulated substantial evidence that they may provide therapeutic benefits for people suffering with psychiatric symptoms. Psychiatric disorders targeted by these psychedelic-assisted therapies are managed with serotonergic drugs like selective serotonin reuptake inhibitors (SSRIs) as the current standard of care, so it is important to evaluate the potential risks of drug-drug interactions and serotonin toxicity (ST) between these agents.

OBJECTIVES

A critical evaluation of the scientific literature is necessary to delineate the risks of ST when combining psychedelics with available serotonergic pharmacotherapy options. This review article describes signs and symptoms of ST, characterizes mechanisms of ST risk, summarizes what is known about serotonergic psychedelic drug interactions, and outlines potential management strategies.

RESULTS

True ST typically occurs with a serotonergic drug overdose or in combinations in which a drug that can increase intrasynaptic serotonin is combined with a monoamine oxidase inhibitor (MAOI). Serotonergic psychotropics that do not contain MAOIs are low risk in combination with psychedelics that also do not contain MAOIs. Signs and symptoms warranting immediate medical attention include myoclonus, extreme and fluctuating vital signs, agitation or comatose mental state, muscle rigidity, pronounced hyperthermia (fever), and/or seizure activity.

CONCLUSIONS

Serotonin-related adverse reactions exist along a spectrum with serotonin syndrome being the most severe manifestations of ST. Due to varying serotonergic mechanisms of psychedelics and psychotropics, with varying propensities to increase intrasynaptic serotonin, some combinations may present a significant risk for serotonin toxicity (ST) while others are likely benign.

Tramadol Use in Perioperative Care and Current Controversies

PURPOSE OF REVIEW

The aim of this review is to discuss the use of tramadol in the perioperative period. There is no doubt that tramadol has revolutionized pain treatment, making it important to understand the pharmacokinetics and pharmacodynamics in order to provide patients with the safest and most effective analgesia.

RECENT FINDINGS

Tramadol is a centrally acting synthetic analgesic with a multimode of action used to help treat moderate to severe pain. Pharmacologically, the unique opioid acts as a serotonin-norepinephrine reuptake inhibitor, while its metabolite, O-desmethyltramadol, acts on the μ-opioid receptor. The analgesic strength of tramadol is about one-tenth that of morphine, making it a relatively safe analgesic. Potential side effects of tramadol include nausea, vomiting, constipation, pruritus, and respiratory depression; however, the severity of these symptoms is minimal compared to traditional opioids. Although some of the perioperative uses of tramadol may be rare, it is a pain management option to consider when alternatives have proved ineffective.

Individual Pharmacotherapy Management (IPM) - I: a group-matched retrospective controlled clinical study on prevention of complicating delirium in the elderly trauma patients and identification of associated factors

Background

Delirium is one of the most frequent complications in hospitalized elderly patients with additional costs such as prolongation of hospital stays and institutionalization, with risk of reduced functional recovery, long-term cognitive impairment, and increased morbidity and mortality. We analyzed the effect of individual pharmacotherapy management (IPM) in the University Hospital Halle in geriatric trauma patients on complicating delirium and aimed to identify associated factors.

Methods

In a retrospective controlled clinical study of 404 hospitalized trauma patients ≥70 years we compared the IPM intervention group (IG) with a control group (CG) before IPM implementation. Delirium was recorded from the hospital discharge letter. The medication review and data records included baseline data, all medications, diagnoses, electrocardiogram (ECG), laboratory and vital parameters during hospitalization. The IPM internist and the senior trauma physician guaranteed personnel and structural continuity in the implementation of the interdisciplinary patient rounds.

Results

There was a highly matched congruence between CG and IG in terms of age, gender, residency, BMI, most diagnoses, and injury patterns to compare the two groups. The total number of medications per patient was 11.1 ± 4.9 (CG) versus 10.4 ± 3.6 (IG). Our targeted IPM focus on 6 frontline aspects with reduction of antipsychotics, anticholinergic burden, benzodiazepines, serotonergic opioids, elimination of pharmacokinetic and pharmacodynamic drug interactions and overdosage reduced complicating delirium from 5% to almost zero at 0.5%. The association of IPM with a significant 10-fold reduction, OR = 0.09 [95% CI 0.01–0.7], in univariable regression, maintained of clinical relevance in multivariable regression OR = 0.1 [95% CI 0.01–1.1]. Factors most strongly associated with complicating delirium in univariable regression were cognitive dysfunction, nursing home residency, muscle relaxants, antiparkinsonian agents, xanthines, transient disorientation documented in the fall risk scale, antibiotic-requiring infections, antifungals, antipsychotics, and intensive care stay, the two latter maintaining significance in multivariable regression.

Conclusions

IPM is associated with a highly effective prevention of complicating delirium in the elderly trauma patients. For patient safety it should be integrated as an essential preventative contribution. The associated factors help identify patients at risk.

The serotonin toxidrome: shortfalls of current diagnostic criteria for related syndromes

INTRODUCTION

Serotonin syndrome (toxicity) describes adverse drug effects from toxic amounts of intra-synaptic central nervous system serotonin. A wide range of drugs have been implicated to cause serotonin toxicity, not all justifiably. The plausible agents all have a final common pathway resulting in a substantial increase in central nervous system serotonergic neurotransmission. Serotonin toxicity is characterized by neuromuscular excitation, mental status changes, and autonomic dysregulation. Signs and symptoms represent a spectrum of toxicity (mild to life-threatening) related to increasing serotonin concentrations. As there is no consensus on the threshold for "toxicity" or diagnostic criteria, the true incidence of serotonin toxicity is unknown. The incidence in overdose is easier to quantify and is reasonably common in serotonergic antidepressant overdoses. In a large case series of overdoses, moderate serotonin toxicity occurred in 14% of poisonings with a selective serotonin reuptake inhibitor. While half those ingesting a monoamine oxidase inhibitor in combination with a serotonergic agent in overdose exhibit at least moderately severe serotonin toxicity. In contrast, the incidence of serotonin toxicity in those on therapeutic serotonergic agents appears to be very low.

OBJECTIVES

To provide a narrative review of the current diagnostic criteria, utilizing case reports of fatalities to evaluate how many meet the various diagnostic criteria and propose practical solutions to resolve controversies in diagnosis.

METHODS

A review of serotonin toxicity diagnostic criteria in the English literature was completed by searching Embase and PubMed from January 1990 to July 2021 for the keywords "serotonin syndrome/toxicity" paired with "diagnostic criteria" or "diagnosis." Also, fatal cases of serotonin toxicity identified from a recent systematic review were independently examined to determine what diagnostic criteria were met and whether serotonin toxicity or another cause was most likely.

REVIEW OF DIAGNOSIS CRITERIA

Serotonin toxicity is a clinical diagnosis, four diagnostic criteria (Sternbach, Serotonin Syndrome Scale, Radomski, and Hunter) have been proposed. However, the Serotonin Syndrome Scale has not been validated in patients with serotonin toxicity and only utilized in those on a serotonergic agent. The remaining three criteria are utilized more widely but have undergone little refinement or validation.

REVIEW OF FATAL CASES

Shortfalls with diagnostic criteria can be illustrated by examining case fatalities. Of 55 fatal cases reviewed, 12 (22%) were unlikely to be serotonin toxicity. Sternbach and Radomski criteria were met by 25 (45%), 20 (36%) had insufficient data reported and 10 (18%) met an exclusion criterion. Few had sufficient information reported to determine whether Hunter Criteria were met, with only 13 (24%) documented as meeting the criteria, the remaining 42 (76%) had insufficient data.

RESOLVING SHORTFALLS IN CURRENT DIAGNOSTIC CRITERIA

As serotonin toxicity is a clinical diagnosis, issues arise when basing the diagnosis on symptom criteria alone, without considering whether the drug/s ingested increase central nervous system serotonin or whether there is an alternative diagnosis. This has resulted in case reports and government warnings for drugs that cannot plausibly cause significant serotonin toxicity (e.g., ondansetron and antipsychotics). We propose when assessing for a serotonin toxidrome, both the causative agent(s) and clinical scenario is considered to determine the likelihood of serotonin toxicity. Then the clinical features assessed, those with a moderate to high prior probability (e.g., serotonergic drug-drug interaction, overdose, recent initiation or increase in dose of serotonergic agent/s) could be diagnosed based on the Hunter criteria. However, those with a low probability (e.g., stable therapeutic doses of a serotonergic agent) require more specific and stringent criteria. Finally, we propose a minimum dataset for case reports/series of serotonin toxicity.

CONCLUSIONS

More complete and accurate reporting of serotonin toxicity cases is required in the future, to avoid further misleading associations that are physiologically implausible.

Escitalopram, bupropion, lurasidone, lamotrigine and possible vortioxetine overdose presented with serotonin syndrome and diffuse encephalopathy: A case report

BACKGROUND

Psychotropic drugs can cause neurological effects when overdosed. This study reports a case of psychotropic drugs overdose presenting with serotonin toxicity and encephalopathy.

CASE PRESENTATION

A 20-year-old female with major depression presented with agitation 3 h after an overdose on multiple medications. Her current medications were vortioxetine, lamotrigine, lurasidone, and bupropion (extended-release). Vital signs showed hyperthermia and tachycardia. Neurological examination was remarkable for mydriasis and hyperreflexia with inducible ankle clonus. The electrocardiography showed sinus tachycardia with QTc 480 ms. Twelve hours later, she became obtunded and developed subcortical myoclonus. The electroencephalogram demonstrated a diffuse encephalopathy pattern without epileptic activities. She was diagnosed with serotonin syndrome based on Hunter Serotonin Toxicity Criteria. Myoclonus and abnormal vital signs resolved within hours after cyproheptadine administration, but she remained unconscious for 3.5 days. Urine drug screening was positive for benzodiazepines and metabolites, lamotrigine, escitalopram, and hydroxybupropion. This suggested she had overdosed on escitalopram which had been previously prescribed. Unfortunately, vortioxetine and lurasidone could not be detected by our current facilities.

CONCLUSION

This case exhibited serotonin syndrome and encephalopathy from overdose of multiple psychotropic agents. Her prolonged depressed consciousness could be explained by the half-life of the drugs and possible drug interactions.

Acute psychosis and serotonin syndrome in the setting of "Triple-C" overdose: a case report

Background

Over-the-counter medication overdose is a difficult diagnostic challenge for many physicians as common drug screening assays cannot detect these substances. We present a case of acute psychosis, serotonin syndrome, and anticholinergic overdose-like properties in the setting of Coricidin HBP Cough & Cold tablets, known by their street name Triple-C. This is the first case report we are aware of involving a patient presenting with these symptoms and requiring critical-care-level support.

Case presentation

A 31-year-old African American female with a past medical history of anxiety, childhood asthma, previous methamphetamine abuse, and coronavirus disease 2019 infection in August 2020 was brought to the emergency department by the local police department with altered mental status. Initial blood work, including extended drug screens, were unremarkable for a definitive diagnosis. This patient required critical-care-level support and high sedation because of her symptoms. Collateral history revealed the patient regularly consumed Triple-C daily for the 6 weeks prior to admission. A trial off sedation was attempted after 24 hours with no complications. The patient admitted to regular Triple-C consumption and auditory hallucinations since adolescence. She was discharged safely after 48 hours back into the community. She was lost to follow-up with psychiatry and internal medicine; however, she was evaluated in the emergency room 1 month later with a similar psychiatric presentation.

Conclusion

Overdose of Triple-C should be kept in the differential diagnosis of patients presenting with a triad of psychosis, serotonin syndrome, and anticholinergic overdose, in the setting of unknown substance ingestion.

Update on Management of the Oral and Maxillofacial Surgery Patient on Selective Serotonin Reuptake Inhibitors

Selective serotonin reuptake inhibitors (SSRIs) have been the cornerstone for the treatment of depression, anxiety, obsessive-compulsive disorder, and panic disorder for a wide spectrum of age groups. Although the beneficial therapeutic properties are well recognized by the medical community, it also possesses many undesirable adverse effects with clinical manifestations. Some of the effects can be severe. This chapter highlights use of SSRIs, the mechanism of action, medication dosages, common drug to drug interactions, and recommendations on management of the oral and maxillofacial surgery patient on SSRIs.

Concomitant treatment with safinamide and antidepressant drugs: Safety data from real clinical practice

BACKGROUND AND PURPOSE

The aim of this study was to assess the possible pharmacological interactions between safinamide and antidepressants, and in particular the appearance of serotonin syndrome with data from real life.

METHODS

We conducted a retrospective observational study of patients with Parkinson's disease from our Movement Disorders Unit, who were under treatment with any antidepressant drug and safinamide. Specifically, symptoms suggestive of serotonin syndrome were screened for. Also, we collected time of simultaneous use, doses of levodopa and other antiparkinsonian drugs.

RESULTS

Clinical records were reviewed for the study period of September 2018 to September 2019. Seventy-eight PD patients who were treated with safinamide of which 25 (32.05%) had a concomitant treatment with an antidepressant drug, being sertraline and escitalopram the most frequent. Mean age was 80 years±8.43 and H&Y stage was 3 [2-4]. Mean dose of levodopa used was 703.75mg±233.15. Median duration of concomitant treatment with safinamide and antidepressant drug was 6 months (IQR 20.5), and over eighteen months in 5 cases. No case of serotonin syndrome was recorded, neither was any of its typical manifestations combined or in isolation.

CONCLUSIONS

Our real clinical practice study suggests that concomitant use of safinamide with antidepressant drugs in PD patients seemed to be safe and well tolerated, even in the long term. However, caution is warranted, individualizing treatment regimens and monitoring the potential appearance of adverse effects.

Dyskinesia-hyperpyrexia syndrome in Parkinson's disease: a systematic review

PURPOSE

Dyskinesia-hyperpyrexia syndrome (DHS) is a rare but life-threatening disease. The clinical manifestations of this syndrome overlap substantially with Parkinson hyperpyrexia syndrome and serotonin syndrome and are often confused by clinicians. The purpose of this review was to enable clinicians to recognize this syndrome and thereby reach a correct diagnosis and provide optimal treatments to improve prognosis in clinical practice.

METHODS

Using the methodology described in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, we conducted a literature search of the PubMed, Embase, and MEDLINE databases using keywords in titles and abstracts of published literature. Quality assessment was performed using the modified Newcastle-Ottawa scale.

RESULTS

A total of 11 patients obtained from nine publications were included in this systematic review. All of the cases occurred in patients with advanced Parkinson's disease (PD) of long disease duration. High ambient temperature was the most common trigger of this syndrome. Hyperpyrexia and dyskinesias were present in all cases. The consciousness disturbances of this syndrome included confusion, hallucination, and lethargy or stupor. Autonomic dysfunction (except for hyperpyrexia) is uncommon in DHS, and only two patients presented with tachycardia. The treatment of this syndrome included supportive interventions (including rehydration, anti-pyretic and anti-infection treatments, and maintaining electrolyte balance), dopaminergic drug reduction and sedation. Two patients died due to DHS.

CONCLUSIONS

We summarized the triggers, clinical features, and treatments of all reported dyskinesia-hyperpyrexia syndrome cases, proposed guiding diagnostic criteria, and established a flow chart to guide diagnoses to quickly identify these three syndromes in clinical practice.

Antiepileptic drugs and serotonin syndrome- A systematic review of case series and case reports

Serotonin syndrome (SS) is a drug‑induced, potentially fatal, clinical syndrome resulting from drugs that have serotonergic properties. Several antiepileptic drugs (AEDs) are known to have serotonergic properties and it can be hypothesized that such AEDs can cause SS. This study aims to review the literature on SS in patients receiving AEDs. We performed a systematic review of Scopus and MEDLINE/PUBMED for case reports and case series of SS where patients had received at least one AED at the onset of symptoms. The cases published in the English literature between 1 January 1991 and 1 April 2021 were included. Initial search identified 1263 articles of which 63 (76 patients) were included in the final analysis. Most of the included cases (53 cases, 70%) have been published in the last 10 years. The mean age of the 76 patients was 40.6 ± 17.8 years, and 51% of cases were females. These patients had been exposed to a total of 8 different types of AEDs. Valproic acid was the most common drug (29, 38%), followed by lamotrigine (22, 29%), gabapentin (16, 21%), pregabalin (seven, 9%), topiramate (five, 7%) and carbamazepine (two, 3%). There has been one case each with phenytoin and oxcarbazepine. Seven (9%) patients received more than one AEDs. Most patients (67, 88%) also received other serotoninergic agents. Only nine (12%) patients were on AEDs alone. The most common clinical condition for using AEDs was psychiatric disorders (36 patients, 47.3%), followed by migraine (17, 22.4%), other painful conditions (15, 19.7%), epilepsy (7, 9.2%), and perioperative conditions (8, 10.5%). Death was reported in two patients. We suggest that AEDs, because of their serotonergic properties, may induce SS, especially in patients who are on another serotonergic agent.

Chronic serotonin syndrome: A retrospective study

BACKGROUND

Serotonin syndrome (SS) is an underdiagnosed drug-induced clinical syndrome resulting from the excess intrasynaptic concentration of serotonin. Very limited information is available about chronic SS.

AIM

To evaluate the epidemiological, clinical, and other aspects of the insidious onset SS.

METHODS

We retrospectively evaluated 14 consecutive adult patients (> 18 years) who had complaints for more than 6 wk at the time of consultation and met the Hunter criteria for SS.

RESULTS

The mean age was 41.1 years (range: 21-61 years), with a male preponderance (64%). Although tremors were observed in all patients, this was a presenting complaint in only 43% of patients. Generalized body pain, insomnia, and restlessness were common presenting features (50% each). Other common clinical features were stiffness of the limbs (43%), diaphoresis (43%), gait disturbances (36%), bowel disturbances (36%), dizziness (29%), sexual dysfunctions (21%), incoordination (14%), and fatigue (14%) The mean duration of symptoms before the diagnosis of SS was 13.5 ± 5.8 wk (range: 6-24 wk). Amitriptyline was the most common drug (n = 6, 43%), followed by tramadol (n = 5, 36%) and sodium valproate (n = 5, 36%). All patients received cyproheptadine, a 5- hydroxytryptamine2A antagonist, as treatment and noted an excellent response over the course of 4-14 d.

CONCLUSION

This study represents the largest study on chronic SS. We suggest that patients receiving serotonergic drugs should be physically examined for the presence of SS upon the development of new symptoms.

Abnormal movements in hospitalized COVID-19 patients: A case series

BACKGROUND

Abnormal movements in Covid-19 patients have been reported with varying degree of frequency, prompting neurologic consultation and additional diagnostic evaluation. We sought to evaluate the frequency and etiology of abnormal movements among hospitalized Covid-19 patients undergoing neurologic consultation.

METHODS

We retrospectively analyzed the first 50 consecutive patients with confirmed Covid-19 hospitalized at our tertiary medical care center who underwent acute inpatient neurology consultation from March 2020 through May 2020. Indication for neurologic consultation and diagnostic studies performed were identified by electronic medical record review.

RESULTS

Of the 50 initial consultation requests, 11 (22.0%) patients were evaluated for abnormal movements (nine male and two female). Myoclonus was diagnosed in 6/11 (54.5%) patients. Additionally, two patients were diagnosed with seizures (confirmed on EEG in one), while two additional patients were diagnosed with tremor (physiologic and probable functional). A single case of serotonin syndrome was also identified.

CONCLUSION

Abnormal movements observed in hospitalized Covid-19 patients can have a wide range of etiologies and were a frequent initial indication for neurologic consultation. Myoclonus was the most frequent type of abnormal movement observed. Early clinical recognition and directed diagnostic work-up is essential for accurate diagnoses in these patients.

Serotonin syndrome in a patient with chronic pain taking analgesic drugs mistaken for psychogenic nonepileptic seizure

Serotonin syndrome (SS) is a potentially life-threatening condition that is caused by the administration of drugs that increase serotonergic activity in the central nervous system. We report a case of serotonin syndrome in a patient with chronic pain who was taking analgesic drugs. A 36-year-old female with chronic pain in the lower back and right buttock area had been taking tramadol hydrochloride 187.5 mg, acetaminophen 325 mg, pregabalin 150 mg, duloxetine 60 mg, and triazolam 0.25 mg daily for several months. After amitriptyline 10 mg was added to achieve better pain control, the patient developed SS, which was mistaken for psychogenic nonepileptic seizure. However, her symptoms completely disappeared after discontinuation of the drugs that were thought to trigger SS and subsequent hydration with normal saline. Various drugs that can increase serotonergic activity are being widely prescribed for patients with chronic pain. Clinicians should be aware of the potential for the occurrence of SS when prescribing pain medications to patients with chronic pain.

Movement Disorder Emergencies

Acute presentation of new movement disorders and acute decompensation of chronic movement disorders are uncommon but potentially life-threatening. Inadvertent or purposeful overdose of many psychiatric medications can result in acute life-threatening movement disorders including serotonin syndrome, neuroleptic malignant syndrome, and malignant catatonia. Early withdrawal of potentiating medications, treatment with benzodiazepines and other diagnosis-specific drugs, and providing appropriate supportive care including airway and breathing management, hemodynamic stabilization, fluid resuscitation, and renal support including possible hemodialysis are the mainstays of acute management. Many of these conditions require admission to the neurologic intensive care unit.

Drug-induced Hyperthermic Syndromes in Psychiatry

Hyperthermia, or extreme elevations in body temperature, can be life-threatening and may be caused by prescription drugs or illegal substances acting at a number of different levels of the neuraxis. Several psychotropic drug classes and combinations have been associated with a classic clinical syndrome of hyperthermia, skeletal muscle hypermetabolism, rigidity or rhabdomyolysis, autonomic dysfunction and altered mental status ranging from catatonic stupor to coma. It is critical for clinicians to have a high index of suspicion for these relatively uncommon drug-induced adverse effects and to become familiar with their management to prevent serious morbidity and mortality. Although these syndromes look alike, they are triggered by quite different mechanisms, and apart from the need to withdraw or restore potential triggering drugs and provide intensive medical care, specific treatments may vary. Clinical similarities have led to theoretical speculations about common mechanisms and shared genetic predispositions underlying these syndromes, suggesting that there may be a common “thermic stress syndrome” triggered in humans and animal models by a variety of pharmacological or environmental challenges.

New psychoactive substances (NPS) and serotonin syndrome onset: A systematic review

The use of several new psychoactive substances (NPS) has become very popular and is posing global health risks. Chemically and pharmacologically diverse molecules are constantly emerging and are presenting with a wide range of clinical implications. Serotonin toxicity, and specifically Serotonin Syndrome (SS), might develop as a result of an over-activation of the serotoninergic system caused by several mechanisms resulting in a classic triad of altered mental status, neuromuscular effects, and autonomic hyperactivity. In the present systematic review, we have investigated and summarized the available evidence related to the association between SS and NPS intake. Three retrospective studies, two case series and five case reports were included in this systematic review; several NPS were found to be implicated in SS occurrence These include psychedelic phenethylamines, e.g. 2, 5-dimethoxy-4-iodophenethylamine (2C-I); 2-(4-Iodo-2,5-dimethoxyphenyl)- N-I[(2-methyoxyphenyl)methyl]ethanamine (25I-NBOMe); and 5-(2-aminopropyl)indole (5-IT); and synthetic cathinones, e.g. mephedrone; 3,4-methylenedioxypyrovalerone (MDPV); methylone; butylone; NRG3; alpha-methyltryptamine (AMT); methoxphenidine (MXP); and the antidepressant bupropion. Bupropion was here misused at high dosages and/or in combination with other licit/illicit serotonergic drugs. Whilst most substances were ingested orally, nasal insufflation (with both 5-IT and 2C-I) and sublingual administration of blotter paper (with 25I-NBOMe) were reported as well. Interestingly, the psychiatric history was negative for most subjects, apart from two cases. Clinicians should be aware of NPS potential risks and the severe consequences of their recreational use, including SS. Also, due to their undetectability in routine and common drug screenings, the diagnostic challenges posed by NPS should not be underestimated during the treatment of such patients.

The prevalence of serotonin syndrome in an intensive care unit: A prospective observational study

PURPOSE

In spite of life-threatening nature of serotonin syndrome (SS), it remains an under-diagnosed condition. The availability of epidemiological data about SS, especially in the ICU setting, may help physicians make early diagnoses and interventions.

MATERIALS AND METHODS

This was a 6-month prospective study in a medical ICU of a tertiary hospital to find out the prevalence of SS. All consecutive adult patients admitted to the medical ICU were evaluated to see if they fulfilled the Hunter criteria of SS. Patients who met the Hunter criteria were evaluated further for other details.

RESULTS

Overall, 309 patients were identified of which 24 (7.8%) met the Hunter criteria. The mean age was 52.4 years, and 75% were male. Most patients received two or more serotonergic drugs. Ondansetron was the most common serotonergic drug (58%), followed by tramadol (38%), and cough syrup (dextromethorphan or chlorpheniramine, 21%). None of the patients received a diagnosis of SS by the treating physicians. Chronic obstructive pulmonary disease exacerbation with respiratory failure and metabolic encephalopathy were the two most common admission diagnoses (17% each). Twenty-two patients received cyproheptadine. There were no fatalities.

CONCLUSION

SS is not uncommon in the ICU setting. There is a need to increase awareness among physicians.

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.

HyperCKemia and rhabdomyolysis in the neuroleptic malignant and serotonin syndromes: A literature review

Neuroleptic malignant syndrome and serotonin syndrome are two syndromes whose molecular bases remain poorly understood. The phenotypes of both syndromes overlap with other syndromes that have a clear genetic background, in particular RYR1-related malignant hyperthermia. Through a literature review, performed according to the PRISMA guidelines, we aimed to report the clinical features of both syndromes, and the results of genetic testing performed. 10 case series and 99 case reports were included, comprising 134 patients. A male predominance of 58% was found. The median age was 35 (range 4-84) years. Eight patients experienced recurrent episodes of rhabdomyolysis. Genetic analysis was performed in eleven patients (8%), revealing four RYR1 variants, three likely benign (p.Asp849Asn, p.Arg4645Gln, p.Arg4645Gln) and one variant of uncertain significance (p.Ala612Thr). This review underlines that a subset of patients with neuroleptic malignant syndrome and serotonin syndrome develop recurrent episodes of rhabdomyolysis. This recurrent pattern suggests a possible underlying (genetic) susceptibility. However, the genetic background of neuroleptic malignant syndrome and serotonin syndrome has only been investigated to a very limited degree so far. The increasing availability of next generation sequencing offers an opportunity to identify potentially associated genetic backgrounds, especially in patients with recurrent episodes or a positive family history.

Serotonin syndrome by drug interactions with linezolid: clues from pharmacovigilance-pharmacokinetic/pharmacodynamic analysis

Purpose

To characterize the post-marketing reporting of serotonin syndrome (SS) due to drug-drug interactions (DDIs) with linezolid and investigate the relationship with pharmacokinetic/pharmacodynamic (PK/PD) properties of serotonergic agents.

Methods

We queried the worldwide FDA Adverse Event Reporting System to extract SS records due to DDIs where linezolid was reported as suspect. For each serotonergic agent concomitantly reported, proportion of SS reports and mean number of DDIs were calculated and three different “SS reporting zones” were created. Relevant PK (peak concentration, area under plasma concentration curve, volume of distribution (V_D), and lipophilicity) and PD (values of binding affinity (Ki) and IC₅₀ for serotonin reuptake transporter (SERT) and 5-HT_2A) parameters were extracted for each serotonergic agent, and relevant PK/PD indexes were calculated to assess correlation with mean number of DDIs (PV index).

Results

Six hundred sixty-nine reports of SS mentioning linezolid were found, being linezolid-citalopram (N = 69; 10.3%) the most frequently DDI reported. Citalopram and methadone showed respectively the highest proportion of SS reports (0.28%) and the lowest mean number of DDIs (1.41). Citalopram, escitalopram, and methadone emerged as red (i.e., alert)-zone medications: they exhibited high lipophilicity and large V_D (proxies of excellent central nervous system penetration) coupled with high potency. Among PK/PD indexes, a significant correlation with PV index was found for V_D/Ki SERT ratio (p = 0.05).

Discussion

Our integrated approach suggests that linezolid is more likely to cause SS when co-administered with citalopram, escitalopram, and methadone, as inferred from their pharmacological properties. Proper management of SS should be tailored on a case-by-case basis.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02990-1) contains supplementary material, which is available to authorized users.

Drinking to death: Hyponatraemia induced by synthetic phenethylamines

Synthetic phenethylamines are widely abused drugs, comprising new psychoactive substances such as synthetic cathinones, but also well-known amphetamines such as methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy). Cathinones and amphetamines share many toxicodynamic mechanisms. One of their potentially life-threatening consequences, particularly of MDMA, is serotonin-mediated hyponatraemia. Herein, we review the state of the art on phenethylamine-induced hyponatremia; discuss the mechanisms involved; and present the preventive and therapeutic measures. Hyponatraemia mediated by phenethylamines results from increased secretion of antidiuretic hormone (ADH) and consequent kidney water reabsorption, additionally involving diaphoresis and polydipsia. Data for MDMA suggest that acute hyponatraemia elicited by cathinones may also be a consequence of metabolic activation. The literature often reveals hyponatraemia-associated complications such as cerebral oedema, cerebellar tonsillar herniation and coma that may evolve to a fatal outcome, particularly in women. Ready availability of fluids and the recommendation to drink copiously at the rave scene to counteract hyperthermia, often precipitate water intoxication. Users should be advised about the importance of controlling fluid intake while using phenethylamines. At early signs of adverse effects, medical assistance should be promptly sought. Severe hyponatraemia (<130 mmol sodium/L plasma) may be corrected with hypertonic saline or suppression of fluid intake. Also, clinicians should be made aware of the hyponatraemic potential of these drugs and encouraged to report future cases of toxicity to increase knowledge on this potentially lethal outcome.

Development of severe serotonin syndrome from acute ingestion of vilazodone without co-ingestion

Vilazodone is a selective serotonin reuptake inhibitor (SSRI) that was introduced to the market in 2011. It has a novel mechanism combining serotonin reuptake and partial agonism of 5HT-1 receptors. It has gained popularity in treating first generation SSRI-resistant depression. There has been little description in the literature of adult overdose. We are describing a 21-year-old female with an intentional overdose of 400 mg of vilazodone. This patient progressively developed worsening serotonin syndrome, which was resistant to aggressive benzodiazepine administration. The patient required sedation with propofol and phenobarbital to control serotonin syndrome. Patient required continued sedation for 36 h post-ingestion, with subsequent extubation and return to normal mental status. We detail an atypical case of a novel SSRI overdose with the treatment regimen used.

A 5-year single-centre retrospective study of potential drug interactions in burns inpatients with psychiatric comorbidities

INTRODUCTION

Burns patients with psychiatric comorbidities may be at increased risk of harm from drug interactions. We aimed to identify the most common classes of drug involved, the potential clinical effects and any clinical evidence for their occurrence.

METHODS

The International Burn Injury Database was used to identify all admission episodes for patients with a psychiatric comorbidity over a 5-year period at an adult regional burns unit. For this group, all drugs administered were categorised as either a new or continuing medication. Following this, an established online tool was used to screen for potential interactions between drugs. Where one was identified, a retrospective notes review was used to investigate whether it had occurred clinically.

RESULTS

Ninety-one admission episodes were identified and records were available for 60 of these. In total, 145 incidences of severe potential interactions were identified (89 between a new drug and a continuing drug and 56 between two new drugs). The most frequently involved continuing drugs with the potential for interaction were neurotransmitter reuptake-inhibiting antidepressants and mirtazapine, while the most common new drugs identified were ondansetron, fentanyl and tramadol. The most frequently identified potential consequence of interactions were serotonin syndrome, arrhythmias and hypokalaemia. Clinically, there was minimal evidence for any interaction.

CONCLUSION

We have found many potential severe interactions in this patient group and psychotropic drugs were more commonly implicated than other drug classes. However, there was little evidence of the clinical manifestations of interaction. Serious drug interactions in burns patients are likely rare, but clinicians should be aware of the most likely drugs involved and the possible sequelae.

Serotonin Syndrome Presenting as a Posterior Reversible Encephalopathy Syndrome

Posterior reversible encephalopathy syndrome (PRES) is a neurological syndrome characterized by an altered level of consciousness, headaches, seizure, and visual changes. PRES has several different etiologies, including malignant hypertension, eclampsia, and certain medications. Here, we describe a 41-year-old woman who presented with altered mental status. She had a preliminary diagnosis of serotonin syndrome as she was on many different serotonin-sparing agents, but her imaging findings were consistent with PRES. After her medications were reviewed and the causative agent was removed, the patient's neurological exam and imaging findings improved, and she returned to her baseline. To our knowledge, this is a unique case of PRES caused by serotonin syndrome secondary to venlafaxine usage.

Behavioral effects of citalopram, tramadol, and binary mixture in zebrafish (Danio rerio) larvae

Pharmaceuticals are emerging as environmentally problematic compounds. As they are often not appropriately removed by sewage treatment plants, pharmaceutical compounds end up in surface water environments worldwide at concentrations in the ng to μg L^-1 range. There is a need to further explore single compound and mixture effects using e.g. in vivo test model systems. We have investigated, for the first time, behavioral effects in larval zebrafish (Danio rerio) exposed to a binary mixture of an antidepressant drug (citalopram) and a synthetic opioid (tramadol). Citalopram and tramadol have a similar mode of action (serotonin reuptake inhibition) and are known to produce drug-drug interactional effects resulting in serotonin syndrome (SS) in humans. Zebrafish embryo-larvae were exposed to citalopram, tramadol and 1:1 binary mixture from fertilization until 144 h post-fertilization. No effects on heart rate, spontaneous tail coiling, or death/malformations were observed in any treatment at tested concentrations. Behavior (hypoactivity in dark periods) was on the other hand affected, with lowest observed effect concentrations (LOECs) of 373 μg L^-1 for citalopram, 320 μg L^-1 for tramadol, and 473 μg L^-1 for the 1:1 mixture. Behavioral EC₅₀ was calculated to be 471 μg L^-1 for citalopram, 411 μg L^-1 for tramadol, and 713 μg L^-1 for the 1:1 mixture. The results of this study conclude that tramadol and citalopram produce hypoactivity in 144 hpf zebrafish larvae. Further, a 1:1 binary mixture of the two caused the same response, albeit at a higher concentration, possibly due to SS.

Serotonin syndrome: a clinical review of current controversies

Serotonin syndrome is a state of increased central and peripheral serotonin (5-hydroxytryptamine) activity. Unless recognized and treated early, serotonin syndrome can lead to seizures, shock and death. Both substances with direct and indirect serotonergic activity can precipitate the syndrome. Serotonin syndrome can occur not only in psychiatric but also in non-psychiatric settings. Yet, clinicians may not be familiar with the condition. We explore some of the current controversies regarding serotonin syndrome. Specifically, we tested the following assumptions: (i) Despite being rare, serotonin syndrome is still clinically relevant; (ii) The Hunter criteria are the gold standard for diagnosing serotonin syndrome; (iii) Hyperthermia is common in cases of serotonin syndrome; (iv) Serotonin syndrome usually develops fast; (v) Severe serotonin syndrome usually or almost exclusively involves monoamine oxidase inhibitors. We found that (i) despite being rare, serotonin syndrome was clinically relevant, (ii) the Hunter criteria could not be regarded as the gold standard for the diagnosis of serotonin syndrome since they missed more cases than the other two diagnostic criteria systems (Sternbach and Radomski criteria), (iii) Serotonin syndrome could occur in the absence of an elevated temperature, (iv) fast onset could not be regarded as a reliable clinical sign of serotonin syndrome, and (v) absence of monoamine oxidase inhibitors treatment did not exclude a diagnosis of serotonin syndrome. Clinicians should bear in mind that in the context of relevant drug history, serotonin syndrome may still be possible in these circumstances.

Serotonin syndrome from sertraline monotherapy

Serotonin syndrome (SS) is a rare, potentially life-threatening adverse drug reaction. Selective serotonin reuptake inhibitors (SSRIs) are among a number of pharmaceuticals that all contribute to SS, but SS caused by SSRI monotherapy is rare. We present a case of probable sertraline-induced SS. A 36-year-old male presented to the emergency department four times in one week with a constellation of autonomic and neuromuscular symptoms. He had been taking sertraline at a therapeutic dose for less than three months. Moderate SS was diagnosed using the Hunter criteria during the fourth visit, when it was seen that he had hyperreflexia and inducible ankle clonus. The patient's symptoms resolved within 24 hours with lorazepam, intravenous fluids, and discontinuation of sertraline. In the emergency department it is important to have a high clinical suspicion for SS even if the patient is taking SSRI monotherapy at therapeutic doses.

Single-Agent Bupropion Exposures: Clinical Characteristics and an Atypical Cause of Serotonin Toxicity

INTRODUCTION

Bupropion is the only Food and Drug Administration-approved synthetic cathinone. It increases the release of norepinephrine in the locus coeruleus and dorsal raphe nucleus, causing an increase in the frequency of serotonergic neuron firing. The diagnosis of serotonin toxicity (ST) from bupropion poisoning is controversial due to the lack of direct serotonergic activity. Nonetheless, there is one documented report of ST after single-agent bupropion overdose and multiple reports describing polypharmacy overdoses where bupropion may have contributed to ST.

METHODS

This is a retrospective analysis of data collected by the Toxicology Investigators Consortium (ToxIC), a prospective multi-center toxico-surveillance and research network registry, from 2014 to 2017. Cases were identified if ST was a clinical effect and bupropion was the single agent listed. Data is presented descriptively.

RESULTS

Of the 266 recorded single bupropion overdoses, the most common symptoms were seizures (47.1%), tachycardia (greater than 140 bpm) (33.9%), agitation (31.7%), toxic psychosis (20.4%), and myoclonus/tremor/hyperreflexia (19%). Benzodiazepines were the most common therapy (69.2%). Thirteen patients (5.9%) were diagnosed with ST by a medical toxicologist.

CONCLUSION

Bupropion overdose is primarily associated with seizures, tachycardia, and agitation; bupropion may be an atypical cause of serotonin toxicity.

Serotonin syndrome following left ventricular assist device implantation: A report and institution-specific strategy for prevention

Serotonin syndrome is a potentially lethal complication of antidepressant therapy. Cardiac surgical patients are at particularly high risk of serotonin syndrome due to the prevalence of depression in patients with advanced cardiac disease, many of whom receive multiple serotonergic agents in the perioperative period. Here, we describe a case of postoperative serotonin syndrome following methylene blue administration for perioperative vasoplegia during left ventricular assist device implantation. We additionally describe an institution-specific strategy to minimize future occurrences of serotonin syndrome in this high-risk population. <Learning objective: Antidepressant medication use is prevalent in advanced heart failure patients. With serotonergic antidepressants, perioperative drug interactions may potentiate serious adverse drug events such as serotonin syndrome. In this report, we describe a case of serotonin syndrome following treatment of perioperative vasoplegia with methylene blue and describe steps our institution has implemented to prevent future occurrences.>.

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.

Serotonin syndrome triggered by postoperative administration of serotonin noradrenaline reuptake inhibitor (SNRI)

Background

Serotonin syndrome is a rare but potentially severe disease, which is caused by hyperstimulation of serotonin receptors in the central nervous system. Several antidepressants exert their effect by modulating intrasynaptic serotonin concentration and anesthetics may affect the metabolism of serotonin, implicating to induce serotonin syndrome in patients taking those antidepressants.

We present a case which provoked serotonin syndrome immediately after taking serotonin noradrenaline reuptake inhibitor (SNRI) in the postoperative period.

Case presentation

A 31-year-old female underwent laparoscopic ovarian cystectomy under general anesthesia with propofol, fentanyl, and remifentanil. She has been taking duloxetine, a SNRI for depression. She developed myoclonus seizure with an increase of blood pressure and heart rate after taking duloxetine on the day after the surgery, which was subsided by a non-selective serotonin receptor antagonist.

Conclusions

Anesthesiologists should be aware of the risk of perioperative serotonin syndrome in patients taking antidepressants affecting serotonin metabolism.

Differential role of dose and environment in initiating and intensifying neurotoxicity caused by MDMA in rats

BACKGROUND

MDMA causes serotonin (5-HT) syndrome immediately after administration and serotonergic injury in a few days or weeks. However, a serotonin syndrome is not always followed by serotonergic injury, indicating different mechanisms responsible for two adverse effects. The goal of present study was to determine causes for two adverse events and further test that dose and environment have a differential role in initiating and intensifying MDMA neurotoxicity.

METHODS

Initiation and intensification were examined by comparing neurotoxic effects of a high-dose (10 mg/kg × 3 at 2 h intervals) with a low-dose (2 mg/kg × 3) under controlled-environmental conditions. Initiation of a serotonin syndrome was estimated by measuring extracellular 5-HT, body-core temperature, electroencephalogram and MDMA concentrations in the cerebrospinal fluid, while intensification determined in rats examined under modified environment. Initiation and intensification of the serotonergic injury were assessed in rats by measuring tissue 5-HT content, SERT density and functional integrity of serotonergic retrograde transportation.

RESULTS

Both low- and high-dose could cause increases in extracellular 5-HT to elicit a serotonin syndrome at the same intensity. Modification of environmental conditions, which had no impact on MDMA-elicited increases in 5-HT levels, markedly intensified the syndrome intensity. Although either dose would cause the severe syndrome under modified environments, only the high-dose that resulted in high MDMA concentrations in the brain could cause serotonergic injury.

CONCLUSION

Our results reveal that extracellular 5-HT is the cause of a syndrome and activity of postsynaptic receptors critical for the course of syndrome intensification. Although the high-dose has the potential to initiate serotonergic injury due to high MDMA concentrations present in the brain, whether an injury is observed depends upon the drug environment via the levels of reactive oxygen species generated. This suggests that brain MDMA concentration is the determinant in the injury initiation while reactive oxygen species generation associated with the injury intensification. It is concluded that the two adverse events utilize distinctly different mediating molecules during the toxic initiation and intensification.

Citalopram overdose and severe serotonin syndrome in an intermediate metabolizing patient

INTRODUCTION

Citalopram is a selective serotonin reuptake inhibitor used for treatment of depression. Metabolism is primarily through CYP3A4 and CYP2C19; activity of the latter can vary depending on genetics. Although rare after single agent exposure, large citalopram ingestions can lead to serotonin syndrome. We report a case of citalopram overdose in an intermediate CYP2C19 metabolizer complicated by severe serotonin syndrome.

CASE DETAILS

A 25-year-old female presented after intentional citalopram overdose with seizures, tachycardia, persistent neuromuscular findings, and severe hyperthermia requiring aggressive sedation and cooling. Protracted symptoms required critical care services throughout a 14 day hospital stay despite traditional treatment of serotonin syndrome. Pharmacogenomic studies revealed intermediate CYP2C19 metabolism which reduces citalopram inactivation and may cause increased levels and toxicity.

DISCUSSION

In the majority of serotonin syndrome cases, symptoms resolve rapidly after treatment initiation and discontinuation of the offending agents. Severe cases are typically associated with ingestion of multiple serotonergic agents. Our patient had severe toxicity after single agent ingestion. Pharmacogenetic testing identified abnormal CYP2C19 activity and previous cases have associated enzyme dysfunction and citalopram toxicity.

CONCLUSION

Citalopram overdose may be associated with severe serotonin syndrome and further investigation is warranted to understand the impact of enzyme genotype on toxicity.

Severe complications of tramadol overdose in Iran

OBJECTIVES

Severe complications of tramadol overdose have been reported; however, few large-scale studies have investigated this issue. Therefore, this study aimed to explore the presentation and complications of tramadol overdose in patients admitted to an intoxication referral center in northwestern Iran.

METHODS

Patients with tramadol overdose admitted to Sina Teaching Hospital in Tabriz, Iran during 2013-2017 were included. For each patient, the following data were collected: demographics, previous drug or medication overdose, whether the patient was in the process of quitting drug use, ingested dose of tramadol and co-ingestants, Glasgow Coma Scale (GCS) score, clinical symptoms at the time of admission, and admission characteristics. Serotonin toxicity was diagnosed in patients who fit the Hunter criteria. Multiple logistic regression was performed to identify variables associated with the incidence of severe complications of tramadol overdose.

RESULTS

In total, 512 cases of tramadol overdose were evaluated, of which 359 patients were included, with a median age of 41 years (range, 16-69) and a median tramadol dose of 1,500 mg (range, 500-4,000). The most frequent complications associated with tramadol overdose were hypertension (38.4%), tachycardia (24.8%), and seizure (14.5%). No serotonin toxicity was detected in patients. Having a GCS score <15, having taken a tramadol dose of >1,000 mg, being in the process of quitting drug use, being 30-49 years old, and male sex were significantly related to the incidence of severe complications of tramadol overdose.

CONCLUSIONS

Although seizure was prevalent among Iranian patients with tramadol poisoning, serotonin toxicity and cardiogenic shock were rare findings.

Individuals with Hyperthyroidism are More Susceptible to having a Serious Serotonin Syndrome Following MDMA (Ecstasy) Administration in Rats

In a recreational use of 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy"), some but not all users are stricken with a serious serotonin (5-hydroxytryptamine; 5-HT) syndrome. This raises a question as to whether there exist subpopulations that are more susceptible to MDMA intoxication. The hypothesis was tested with hyperthyroid versus euthyroid rats by measuring changes in body-core temperature (T _cor) and 5-HT in the hypothalamus. In the euthyroid rats, injection of MDMA at a recreationally relevant dose had no serious effect on T _cor. In contrast, the same dose was sufficient to evoke life-threatening hyperthermia in hyperthyroid rats. Neurochemical studies revealed that there was greater 5-HT efflux in the hyperthyroid than the euthyroid rats. These effects were blocked by pretreatment with M100907, a 5-HT_2A receptor antagonist. In summary, our data support the hypothesis that individuals with hyperthyroidism are more susceptible to having a serious serotonin syndrome following MDMA administration.