Drug-Induced Serotonin Syndrome

Neuroleptic malignant syndrome and serotonin syndrome: a comparative bibliometric analysis

OBJECTIVE

This study aimed to analyze and map scientific literature on Neuroleptic Malignant Syndrome (NMS) and Serotonin Syndrome (SS) from prestigious, internationally indexed journals. The objective was to identify key topics, impactful articles, prominent journals, research output, growth patterns, hotspots, and leading countries in the field, providing valuable insights for scholars, medical students, and international funding agencies.

METHODS

A systematic search strategy was implemented in the PubMed MeSH database using specific keywords for NMS and SS. The search was conducted in the Scopus database, renowned for its extensive coverage of scholarly publications. Inclusion criteria comprised articles published from 1950 to December 31st, 2022, restricted to journal research and review articles written in English. Data were analyzed using Microsoft Excel for descriptive analysis, and VOSviewer was employed for bibliometric mapping.

RESULTS

The search yielded 1150 articles on NMS and 587 on SS, with the majority being case reports. Growth patterns revealed a surge in NMS research between 1981 and 1991, while SS research increased notably between 1993 and 1997. Active countries and journals differed between NMS and SS, with psychiatry journals predominating for NMS and pharmacology/toxicology journals for SS. Authorship analysis indicated higher multi-authored articles for NMS. Top impactful articles focused on review articles and pathogenic mechanisms. Research hotspots included antipsychotics and catatonia for NMS, while SS highlighted drug interactions and specific medications like linezolid and tramadol.

CONCLUSIONS

NMS and SS represent rare but life-threatening conditions, requiring detailed clinical and scientific understanding. Differential diagnosis and management necessitate caution in prescribing medications affecting central serotonin or dopamine systems, with awareness of potential drug interactions. International diagnostic tools and genetic screening tests may aid in safe diagnosis and prevention. Reporting rare cases and utilizing bibliometric analysis enhance knowledge dissemination and research exploration in the field of rare drug-induced medical conditions.

SOX1 Antibody in a Patient With Serotonin Syndrome

SOX1 antibody is an autoimmune antibody, usually associated with Lambert-Eaton myasthenic syndrome, paraneoplastic conditions, and encephalitis. This antibody has also been found among psychiatric patients. However, the role of SOX1 antibody in serotonin syndrome has not yet been defined, as a literature search yielded no results. Therefore, the treatment as such has unknown clinical significance. In this case study, we report a patient with SOX1 antibodies and altered mental status out of proportion to serotonin syndrome whose symptoms improved with simultaneous treatment of both conditions.

Serotonin Syndrome: An Emerging Reality in the Emergency Department

Serotonin syndrome (SS) is an entity caused by interference with the serotonin metabolism and/or by medications that act as serotonin receptor agonists. The signs and symptoms are nonspecific, making the diagnosis challenging. Treatment depends on the severity of the manifestations. In mild to moderate cases, it typically resolves within the first 24 hours after initiating therapy and discontinuation of the serotoninergic medications. A 42-year-old woman with a previous history of depression was admitted to the hospital due to the voluntary ingestion of multiple tablets of escitalopram 10 mg and venlafaxine 75 mg. Physical examination showed a hyperthermic and diaphoretic patient. Tremor, agitation, bilateral ocular clonus, and spontaneous inferior limb clonus were also present. Hunter's criteria were applied, and the diagnosis of SS was assumed. Supportive and symptomatic treatments were initiated. The evolution was benign, with symptomatic remission in the first 24 hours. In the last decades, a large increase in the use of antidepressants was noted, and, as such, defining SS as rare is no longer appropriate. Delaying the treatment can dictate an increase in morbidity and mortality. It is important to highlight that the diagnosis is mainly clinical as diagnostic criteria may miss out on some cases. As such, clinical awareness of SS's multiplicity of presentations is of utmost importance.

Persons With Spinal Cord Injury Report Peripherally Dominant Serotonin-Like Syndrome After Use of Serotonergic Psychedelics

Psychedelic-assisted therapy (PAT) may treat various mental health conditions. Despite its promising therapeutic signal across mental health outcomes, less attention is paid on its potential to provide therapeutic benefits across complex medical situations within rehabilitation medicine. Persons with spinal cord injury (SCI) have a high prevalence of treatment-resistant mental health comorbidities that compound the extent of their physical disability. Reports from online discussion forums suggest that those living with SCI are using psychedelics, though the motivation for their use is unknown. These anecdotal reports describe a consistent phenomenon of neuromuscular and autonomic hypersensitivity to classical serotonergic psychedelics, such as psilocybin and lysergic acid diethylamide (LSD). Persons describe intense muscle spasms, sweating, and tremors, with an eventual return to baseline and no reports of worsening of their baseline neurological deficits. The discomfort experienced interferes with the subjective beneficial effects self-reported. This phenomenon has not been described previously in the academic literature. We aim to provide a descriptive review and explanatory theoretical framework hypothesizing this phenomenon as a peripherally dominant serotonin syndrome-like clinical picture-that should be considered as such when persons with SCI are exposed to classical psychedelics. Raising awareness of this syndrome may help our mechanistic understanding of serotonergic psychedelics and stimulate development of treatment protocols permitting persons with SCI to safely tolerate their adverse effects. As PAT transitions from research trials into accepted clinical and decriminalized use, efforts must be made from a harm reduction perspective to understand these adverse events, while also serving as an informed consent process aid if such therapeutic approaches are to be considered for use in persons living with SCI.

Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2D6, CYP2C19, CYP2B6, SLC6A4, and HTR2A Genotypes and Serotonin Reuptake Inhibitor Antidepressants

Serotonin reuptake inhibitor antidepressants, including selective serotonin reuptake inhibitors (SSRIs; i.e., citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline), serotonin and norepinephrine reuptake inhibitors (i.e., desvenlafaxine, duloxetine, levomilnacipran, milnacipran, and venlafaxine), and serotonin modulators with SSRI-like properties (i.e., vilazodone and vortioxetine) are primary pharmacologic treatments for major depressive and anxiety disorders. Genetic variation in CYP2D6, CYP2C19, and CYP2B6 influences the metabolism of many of these antidepressants, which may potentially affect dosing, efficacy, and tolerability. In addition, the pharmacodynamic genes SLC6A4 (serotonin transporter) and HTR2A (serotonin-2A receptor) have been examined in relation to efficacy and side effect profiles of these drugs. This guideline updates and expands the 2015 Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for CYP2D6 and CYP2C19 genotypes and SSRI dosing and summarizes the impact of CYP2D6, CYP2C19, CYP2B6, SLC6A4, and HTR2A genotypes on antidepressant dosing, efficacy, and tolerability. We provide recommendations for using CYP2D6, CYP2C19, and CYP2B6 genotype results to help inform prescribing these antidepressants and describe the existing data for SLC6A4 and HTR2A, which do not support their clinical use in antidepressant prescribing.

G protein-coupled receptors in neurodegenerative diseases and psychiatric disorders

Neuropsychiatric disorders are multifactorial disorders with diverse aetiological factors. Identifying treatment targets is challenging because the diseases are resulting from heterogeneous biological, genetic, and environmental factors. Nevertheless, the increasing understanding of G protein-coupled receptor (GPCR) opens a new possibility in drug discovery. Harnessing our knowledge of molecular mechanisms and structural information of GPCRs will be advantageous for developing effective drugs. This review provides an overview of the role of GPCRs in various neurodegenerative and psychiatric diseases. Besides, we highlight the emerging opportunities of novel GPCR targets and address recent progress in GPCR drug development.

Neuropathic pain: Mechanisms and therapeutic strategies

The physiopathology and neurotransmission of pain are of an owe inspiring complexity. Our ability to satisfactorily suppress neuropathic or other forms of chronic pain is limited. The number of pharmacodynamically distinct and clinically available medications is low and the successes achieved modest. Pain Medicine practitioners are confronted with the ethical dichotomy imposed by Hippocrates: On one hand the mandate of primum non nocere, on the other hand, the promise of heavenly joys if successful divinum est opus sedare dolorem. We briefly summarize the concepts associated with nociceptive pain from nociceptive input (afferents from periphery), modulatory output [descending noradrenergic (NE) and serotoninergic (5-HT) fibers] to local control. The local control is comprised of the "inflammatory soup" at the site of pain origin and synaptic relay stations, with an ATP-rich environment promoting inflammation and nociception while an adenosine-rich environment having the opposite effect. Subsequently, we address the transition from nociceptor pain to neuropathic pain (independent of nociceptor activation) and the process of sensitization and pain chronification (transient pain progressing into persistent pain). Having sketched a model of pain perception and processing we attempt to identify the sites and modes of action of clinically available drugs used in chronic pain treatment, focusing on adjuvant (co-analgesic) medication.

Recognition and Management of Serotonin Toxidrome in the Emergency Department-Case Based Review

Serotonin syndrome (SS) is a clinical toxidrome with high variability in clinical practice. It develops due to increased serotonin levels in the central nervous system. With an underestimated frequency, SS can develop following an overdose, a therapeutic dose increase, or drug to drug interaction of at least one serotonergic agent. It can present with autonomic signs, neuromuscular changes and an altered mental status. However, history and clinical examination are key features to formulate the diagnosis. Treatment options consist of supportive measures, discontinuation of the offending agent and certain therapeutic agents previously reported to improve outcomes. Physicians have limited experience with SS, partially due to the lack of its identification in clinical practice. Therefore, we have integrated, in a narrative review, the case of a young male with SS following an atypical antipsychotic overdose superimposed on chronic treatment with agents previously known to produce SS.

Multimodal analgesic protocol for cervical disc replacement in the ambulatory setting: Clinical case series

Background

Effective pain management is paramount for outpatient surgical success. This study aims to report a case series of patients undergoing cervical disc replacement (CDR) in an ambulatory surgery center (ASC) with the use of an enhanced multimodal analgesic (MMA) protocol.

Methods

Primary, single-/2-level CDR procedures at an ASC with an enhanced MMA protocol were included. ASC patients were discharged day of surgery. Patient-reported outcome measures (PROMs) were administered at preoperative/6-week/12-week/6-month/1-year/2-year timepoints and included Visual Analogue Scale (VAS) neck, VAS arm, Neck Disability Index (NDI), Patient-Reported Outcomes Measurement Information System-Physical Function (PROMIS-PF), and 12-Item Short-Form Physical and Mental Composite Score (SF-12 PCS/SF-12 MCS). A t-test assessed postoperative PROM improvement from baseline. MCID achievement was determined by comparing ΔPROM scores to previously established thresholds.

Results

106 patients were included, 76 single-level and 30 2-level. Most single-levels occurred at C5-C6, most 2-levels at C5-C7. One 2-level patient developed a hematoma 5 days postoperatively and underwent revision for evacuation. Five patients reported postoperative dysphagia; all were quickly resolved. One patient had an episode of seizure secondary to serotonin syndrome from concealed drug use. Patient was reintubated, transferred, and treated for serotonin syndrome. Two patients experienced postoperative nausea/vomiting. Cohort significantly improved from baseline for all PROMS at all timepoints except SF-12 MCS at 1-year/2-years and SF-12 PCS at 2 years (p < 0.047, all). Overall MCID achievement rates were: VAS arm (48.7%), VAS neck (69.1%), NDI (98.9%), SF-12 MCS (50.0%), SF-12 PCS (54.6%), and PROMIS-PF (73.4%).

Conclusion

Outpatient CDR, incorporating an enhanced MMA protocol, can be safely and effectively performed with proper patient selection and surgical technique. Patients saw timely discharge, well-controlled postoperative pain, and favorable long-term outcomes.

Clinically Relevant Drug Interactions with Monoamine Oxidase Inhibitors

Monoamine oxidase inhibitors (MAOI) are a class of drugs that were originally developed for the treatment of depression but have since been expanded to be used in management of affective and neurological disorders, as well as stroke and aging-related neurocognitive changes. Ranging from irreversible to reversible and selective to non-selective, these drugs target the monoamine oxidase (MAO) enzyme and prevent the oxidative deamination of various monoamines and catecholamines such as serotonin and dopamine, respectively. Tyramine is a potent releaser of norepinephrine (NE) and is found in high concentrations in foods such as aged cheeses and meats. Under normal conditions, NE is unable to accumulate to toxic levels due to the presence of MAO-A, an enzyme that degrades neurotransmitters, including NE. When MAO-A is inhibited, the capacity to handle tyramine intake from the diet is significantly reduced causing the brain to be vulnerable to overstimulation of postsynaptic adrenergic receptors with as little as 8-10 mg of tyramine ingested and can result in life-threatening blood pressure elevations. In addition to adverse reactions with certain foods, both older and newer MAOIs can negatively interact with both sympathomimetic and serotonergic drugs. In general, patients on a MAOI want to avoid two types of medications: those that can elevate blood pressure via sympathomimetic actions (e.g., phenylephrine and oxymetazoline) and those that can increase serotonin levels via 5-HT reuptake inhibition (e.g., dextromethorphan, chlorpheniramine, and brompheniramine). Illicit drugs that stimulate the central nervous system such as ecstasy (MDMA, 3,4-methylenedioxymethamphetamine) act as serotonin releasers. Patient involvement is also crucial to ensure any interaction within the healthcare setting includes making other providers aware of a MAOI prescription as well as avoiding certain OTC medications that can interact adversely with MAOIs.

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.

Maternal Prepregnancy 5-Hydroxytryptamine Exposure Affects the Early Development of the Fetus

In recent decades, the increasing incidence of depression has contributed to an increase in the use of serotonergic drugs, such as antidepressants, which predisposes humans to serotonin syndrome. Serotonin syndrome is caused by elevated serotonin levels in the central and peripheral nervous systems. It has been well documented that the development of offspring can be affected by maternal exposure to environmental challenges, such as stress, diseases, or an unhealthy diet during pregnancy. Serotonin, also called 5-hydroxytryptamine (5-HT), is widely expressed in the female reproductive system and plays an important role in the development of follicles and embryos. However, whether the suffering of the mother from serotonin syndrome before pregnancy affects fetal development is still uncertain. In the present study, to explore the effect of maternal prepregnancy 5-HT exposure on the fetus, intraperitoneal injection of 5-HT was used to change maternal prepregnancy 5-HT levels. It was found that maternal prepregnancy 5-HT exposure significantly reduced the body weight and liver weight and the levels of estrogen and progesterone in female mice. Although there was no significant difference in the cleavage rate and blastocyst rate between the 5-HT and control groups, maternal prepregnancy 5-HT exposure increased the percentage of embryo resorption, decreased placental weight, and led to placental inflammation at E13.5. Notably, 5-HT exposure caused weight loss in the offspring at 2 weeks. These results suggested that maternal prepregnancy 5-HT exposure could affect the development of the offspring, which was partly caused by reduced hormonal secretion and placental inflammation.

Novel Phenethylamines and Their Potential Interactions With Prescription Drugs: A Systematic Critical Review

BACKGROUND

The novel phenethylamines 4-fluoroamphetamine (4-FA) and 2,5-dimethoxy-4-bromophenethylamine (2C-B) fall in the top 10 most used new psychoactive substances (NPSs) among high-risk substance users. Various phenethylamines and NPS are also highly used in populations with mental disorders, depression, or attention deficit hyperactivity disorder (ADHD). Moreover, NPS use is highly prevalent among men and women with risky sexual behavior. Considering these specific populations and their frequent concurrent use of drugs, such as antidepressants, ADHD medication, and antiretrovirals, reports on potential interactions between these drugs, and phenethylamines 4-FA and 2C-B, were reviewed.

METHODS

The authors performed a systematic literature review on 4-FA and 2C-B interactions with antidepressants (citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, duloxetine, bupropion, venlafaxine, phenelzine, moclobemide, and tranylcypromine), ADHD medications (atomoxetine, dexamphetamine, methylphenidate, and modafinil), and antiretrovirals.

RESULTS

Limited literature exists on the pharmacokinetics and drug-drug interactions of 2C-B and 4-FA. Only one case report indicated a possible interaction between 4-FA and ADHD medication. Although pharmacokinetic interactions between 4-FA and prescription drugs remain speculative, their pharmacodynamic points toward interactions between 4-FA and ADHD medication and antidepressants. The pharmacokinetic and pharmacodynamic profile of 2C-B also points toward such interactions, between 2C-B and prescription drugs such as antidepressants and ADHD medication.

CONCLUSIONS

A drug-drug (phenethylamine-prescription drug) interaction potential is anticipated, mainly involving monoamine oxidases for 2C-B and 4-FA, with monoamine transporters being more specific to 4-FA.

Concurrent Serotonin Syndrome and Prolong QT Interval Induced by Paroxetine Overdose With Isotretinoin

The use of serotonergic drugs has increased in the last decade especially selective serotonin reuptake inhibitors (SSRIs) with increased indications. Serotonin syndrome (SS) and QT prolongation are serious adverse reactions of SSRI use, they usually occur with concomitant use of two or more serotonergic medication. Herein, we are presenting an interesting unique case of SS and prolongation of QT interval after a suicidal attempt in a patient on isotretinoin with paroxetine overdosing. The prolongation of QT interval observed in this case could be related to isotretinoin synergistic effect. The risk of suicide and side effects of SSRI with isotretinoin, especially in patient with psychiatric illness would be a huge concern. This case hopes to raise the awareness of the risks when prescribing SSRI and isotretinoin in this group of patients.

Exposure to tricyclic antidepressant nortriptyline affects early-life stages of zebrafish (Danio rerio)

Psychiatric drugs are among the leading medications prescribed for humans, with their presence in aquatic environments raising concerns relating to potentially harmful effects on non-target organisms. Nortriptyline (NTP) is a selective serotonin-norepinephrine reuptake inhibitor antidepressant, widely used in clinics and found in environmental water matrices. In this study, we evaluated the toxic effects of NTP on zebrafish (Danio rerio) embryos and early larval stages. Developmental and mortality analyses were performed on zebrafish exposed to NTP for 168 h at concentrations ranging from 500 to 46,900 µg/L. Locomotor behaviour and acetylcholinesterase (AChE) activity were evaluated by exposing embryos/larvae to lower NTP concentrations (0.006-500 µg/L). The median lethal NTP concentration after 168 h exposure was 2190 µg/L. Although we did not identify significant developmental changes in the treated groups, lack of equilibrium was already visible in surviving larvae exposed to ≥ 500 µg/L NTP. The behavioural analyses showed that NTP was capable of modifying zebrafish larvae swimming behaviour, even at extremely low (0.006 and 0.088 µg/L) environmentally relevant concentrations. We consistently observed a significant reduction in AChE activity in the animals exposed to 500 µg/L NTP. Our results highlight acute toxic effects of NTP on the early-life stages of zebrafish. Most importantly, exposure to environmentally relevant NTP concentrations may affect zebrafish larvae locomotor behaviour, which in turn could reduce the fitness of the species. More studies involving chronic exposure and sensitive endpoints are warranted to better understand the effect of NTP in a more realistic exposure scenario.

Analyzing cannabinoid-induced abnormal behavior in a zebrafish model

In this study, we investigated locomotor activity and responses to repeated light and dark stimuli to assess cannabinoid-induced abnormal behavior in zebrafish larvae (Danio rerio), as an alternative to standard rodent models. To induce the desired responses, we used cannabidiol and WIN55,212-2, two major cannabinoid components. A repeated light and dark test was used to assess how drug exposure influences locomotory responses. Larvae were examined after moderate cannabidiol and WIN55,212-2 exposure and at 24 h after transfer to untreated water. We found that cannabidiol did not produce a dose-dependent inhibitory effect on locomotor activity, with both 0.5 and 10 μg/mL concentrations reducing movement velocity and the total distance moved. However, 10 μg/mL cannabidiol was observed to attenuate the responses of larvae exposed to darkness. No differences were detected between the control and cannabidiol-treated groups after 24 h in fresh water. Fish treated with WIN55,212-2 at 0.5 and 1 μg/mL showed virtually no activity, even in darkness, whereas a concentration of 10 μg/mL induced mortality. A 24-h period in fresh water had the effect of reversing most of the drug-induced immobilization, even in the WIN55,212-2-treated groups. Larvae were also evaluated for their responses to cannabidiol subsequent to an initial exposure to WIN55,212-2, and it was accordingly found that treatment with cannabidiol could attenuate WIN55,212-2-induced abnormal immobilization, whereas equivalent doses of cannabidiol and WIN55,212-2 produced a mixed response. In conclusion, the behavioral effects of the two cannabinoids cannabidiol and WIN55,212-2 appear to be ratio dependent. Furthermore, the repeated light and dark test could serve as a suitable method for assaying drug-induced behavior.

Divergent pathways mediate 5-HT1A receptor agonist effects on close social interaction, grooming and aggressive behaviour in mice: Exploring the involvement of the oxytocin and vasopressin systems

BACKGROUND

5-HT_1A receptor (5-HT_1AR) abnormalities are implicated in aggression, and there has been considerable interest in developing 5-HT_1AR agonists for treating aggression. Endogenous oxytocin (OXT) released upon stimulation of 5-HT_1ARs in the hypothalamus mediates at least some of the effects of 5-HT_1AR agonists on social behaviour.

AIMS

Given 5-HT_1AR, OXT receptor (OXTR) and vasopressin V1a receptor (V1aR) agonists can all reduce aggression, the current study aimed to determine whether the anti-aggressive effects of 5-HT_1AR stimulation can also be explained by downstream actions at OXTRs and/or V1aRs in a mouse model of non-territorial, hyper-aggressive behaviour.

METHODS

Male Swiss mice (N=80) were socially isolated or group housed for six weeks prior to the start of testing. Testing involved placing two unfamiliar weight- and condition-matched mice together in a neutral context for 10 minutes.

RESULTS

Social isolation led to a pronounced increase in aggressive behaviour, which was dose-dependently inhibited by the 5-HT_1AR agonist 8-OH-DPAT (0.1, 0.3 and 1 mg/kg intraperitoneally (i.p.)), with accompanying increases in close social contact (huddling) and grooming. The effects of 8-OH-DPAT on aggression, huddling and grooming were blocked by pretreatment with a selective 5-HT_1AR antagonist (WAY-100635; 0.1 mg/kg i.p.). The anti-aggressive effects of 8-OH-DPAT were unaffected by an OXTR antagonist (L-368,899; 10 mg/kg i.p.), whereas the effects on huddling and grooming were inhibited. Pretreatment with a V1aR antagonist (SR49059; 20 mg/kg i.p.) had no effect.

CONCLUSIONS

Our study suggests that stimulation of endogenous oxytocin is involved in the effects of 5-HT_1AR activation on close social contact and grooming but not aggression.

Metoclopramide-induced Serotonin Syndrome

Serotonin syndrome is a clinical diagnosis characterized by a constellation of autonomic and neurological physical examination findings due to the use of one or more serotonergic agents. Due to high morbidity and mortality associated with this condition, high index of suspicion is required in making this diagnosis. Treatment is aimed at discontinuation of the offending agent and supportive care. We present a case of a 28-year-old woman who presented with acetaminophen toxicity, however developed iatrogenic serotonin syndrome due to use of scheduled intravenous metoclopramide. Metoclopramide, by itself, very rarely causes serotonin syndrome and typically results in this condition when used in combination with other pro-serotonergic agents.

A Case Report of Serotonin Syndrome in a Patient on Selective Serotonin Reuptake Inhibitor (SSRI) Monotherapy

INTRODUCTION

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) with several indications, one of which is for depression. We present a case of probable paroxetine-induced serotonin syndrome.

CASE SUMMARY

A 21-year-old female with a history of generalized anxiety disorder and major depression presented with increased depressive symptoms over several months while taking fluoxetine 20 mg daily. Fluoxetine was discontinued without taper and replaced with paroxetine 10 mg daily, along with hydroxyzine 50 mg twice daily as needed for anxiety. Within a week of starting the paroxetine, the patient reported increased anxiety, insomnia, and constant shaking. The paroxetine continued to be uptitrated over a 3-week period to a dose 30 mg due to unremitting depressive symptoms. One month later, the patient presented with tachycardia, generalized body aches, extreme fatigue, weakness, uncontrollable twitching, tremor, and hyperreflexia. A widespread burning sensation accompanied by random hot flashes without diaphoresis was also noted. Serotonin syndrome was diagnosed using the Hunters criteria. Paroxetine was discontinued, and the patient's physical symptoms resolved within a week.

DISCUSSION

To date, only 5 cases of serotonin syndrome have been reported in patients receiving SSRI monotherapy at recommended therapeutic doses.

Network-Based Assessment of Adverse Drug Reaction Risk in Polypharmacy Using High-Throughput Screening Data

The risk of adverse drug reactions increases in a polypharmacology setting. High-throughput drug screening with transcriptomics applied to human cells has shown that drugs have effects on several molecular pathways, and these affected pathways may be predictive proxy for adverse drug reactions. Depending on the way that different drugs may contribute to adverse drug reactions, different options may exist in the clinical setting. Here, we formulate a network framework to integrate the relationships between drugs, biological functions, and adverse drug reactions based on the high-throughput drug perturbation data from the Library of Integrated Network-Based Cellular Signatures (LINCS) project. We present network-based parameters that indicate whether a given reaction may be related to the effect of a single drug or to the combination of several drugs, as well as the relative risk of adverse drug reaction manifestation given a certain drug combination.

Distinct Gut Microbiota Composition and Functional Category in Children With Cerebral Palsy and Epilepsy

Cerebral palsy (CP) and epilepsy are two interactive neurological diseases, and their clinical treatment can cause severe side-effects in children's development, especially when it involves long-term administration of antiepileptic drugs. Accumulating studies on the gut-brain axis indicated that the gut microbiota (GM), which participates in various neurological diseases, would provide a harmless therapeutic target for the treatment of CP and epilepsy. To explore the GM characteristics in children with both CP and epilepsy (CPE), we collected fecal samples from 25 CPE patients (CPE group) and 21 healthy children (Healthy group) for 16S rDNA sequencing. In this study, we discovered significantly higher microbial diversity in the CPE group compared to healthy group (P < 0.001). After selecting the top 15 most abundant genera in each group, we found significantly enriched Bifidobacterium, Streptococcus, Akkermansia, Enterococcus, Prevotella, Veillonella, Rothia, and Clostridium IV in the CPE group, and noticeably reduced Bacteroides, Faecalibacterium, Blautia, Ruminococcus, Roseburia, Anaerostipes, and Parasutterella. A GM co-occurrence network was also constructed, and negative correlations were discovered between Bacteroides and Lactobacillus (r = -0.768, P < 0.001, FDR < 0.001), as well as Intestinibacter and Bifidobacterium (r = -0.726, P < 0.001, FDR < 0.001). After KEGG annotation and functional enrichment, 24 functional categories exhibited different enrichment levels between the CPE and Healthy groups. The functions, associated with xenobiotics metabolism, immune system diseases, and neurodegenerative diseases, were enriched in the CPE group. Conversely, the functional categories related to the biosynthesis of secondary metabolites were reduced. Furthermore, the neurodegenerative diseases were mainly attributed to Streptococcus, while an increased risk of immune system diseases was associated with enriched Akkermansia in the CPE patients. Generally, this study characterized the GM in CPE patients, illustrated the microbial co-occurrence relationships, and detected the functional distributions of the bacteria.