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

Analgesic treatment for refractory cancer pain caused by gastric cancer bone metastasis: A case report and literature review

RATIONALE

Patients with bone metastasis-associated cancer pain often experience a complex mix of pain types. Consequently, the use of multimodal combination therapy is essential. While monitoring for common adverse reactions in pain treatment, it is also crucial to be vigilant for the rare but serious serotonin syndrome.

PATIENT CONCERNS

A 53-year-old female with metastatic gastric cancer was hospitalized due to severe, uncontrolled thoracic and cervical pain. During the titration of her cancer pain medication, she developed serotonin syndrome.

DIAGNOSES

He was diagnosed with refractory cancer pain and serotonin syndrome.

INTERVENTIONS

The complete process of cancer pain medication in a patient with gastric cancer and bone metastasis was analyzed, with a primary focus on the selection of analgesic medications, adjustment of opioid dosages, and prevention and treatment of medication-associated adverse reactions.

OUTCOMES

The patient's cancer pain was well controlled, with the prompt management of adverse reactions. Furthermore, by adjusting the medication regimen, intolerable adverse reactions were prevented.

LESSONS

In clinical settings, personalized analgesic regimens must be developed for patients with cancer pain to enhance patient compliance with medication, prevent the occurrence of severe adverse reactions, and improve the overall quality of life of patients with cancer. Healthcare professionals should pay increased attention to ADRs associated with opioid medications, whereas pharmacists should assist them in promptly identifying ADRs.

Risk of stress cardiomyopathy associated with selective serotonin reuptake inhibitors and serotonin and norepinephrine reuptake inhibitors: a real-world pharmacovigilance analysis

Selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) are reported to cause stress cardiomyopathy (SC). This study evaluated the association between SSRI/SNRI use and the occurrence of cardiomyopathy in the publicly available U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) database. Disproportionate analysis and likelihood ratio tests were used to identify risk associated with SSRIs or SNRIs and the incidence of SC, using data from between from 2012 to 2022 acquired from the FAERS database. The study identified 132 individual case safety reports (ICSRs) of SC associated with SSRIs or SNRIs. Venlafaxine (48%) and fluoxetine (27%) were the most common antidepressants of the ICSRs. Approximately 80% of SC cases were reported in females, with individuals aged 45-65 years identified as a high-risk population. Both venlafaxine (ratio-scale information component [RSIC] 2.54, 95% CI 2.06-3.04) and fluoxetine (RSIC 3.20, 95% CI 2.31-4.47) were associated with SC, with likelihood ratio estimates of 3.55 (p = 0.02) for venlafaxine and 4.82 (p = 0.008) for fluoxetine. The median time to cardiomyopathy onset was 20 days, with hospitalization reported in 48.33% of patients. Venlafaxine and fluoxetine were associated with SC risk, particularly in middle-aged women. Caution should be exercised when using SSRIs or SNRIs combined with other serotonergic medications.

Management of serotonin syndrome (toxicity)

Serotonin syndrome (toxicity), resulting from an excessive accumulation of serotonin in the central nervous system, it can occur due to various factors such as the initiation of medication, overdose or drug interactions. Diagnosing serotonin toxicity presents challenges as there are no definitive criteria. This review delves into the pathophysiology, incidence, clinical assessment and management of serotonin toxicity, stressing the significance of promptly recognizing and managing severe cases. Diagnosis relies primarily relies on clinical assessment due to the absence of specific laboratory tests. The Hunter Serotonin Toxicity criteria are commonly utilized but have only been validated in the overdose setting. Assessing the severity of toxicity is crucial for guiding management decisions. Supportive care, discontinuation of causative agents and symptomatic treatment are prioritized in management. Mild toxicity often requires withdrawal or reduction of the serotonergic agent, while more severe toxicity requires more aggressive resuscitative and supportive care. Severe serotonin toxicity characterized by hyperthermia and rigidity requires aggressive supportive measures, including benzodiazepines, intubation, paralysis and active cooling. Animal studies suggest potential benefits of 5-HT2A receptor antagonists in preventing hyperthermia and fatalities, but only at high doses. Their clinical effectiveness remains uncertain, and evidence is predominately from case series and case reports. Although commonly used, serotonin antagonists like cyproheptadine lack conclusive evidence of efficacy. Other serotonin antagonists such as chlorpromazine and olanzapine have been explored but evidence is limited to case reports. Hence, the cornerstone of treating severe cases does not lie in 'antidote' administration or even diagnosis but in effective early resuscitative and supportive care.

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.

Post-marketing safety concerns with lumateperone: a pharmacovigilance analysis based on the FDA adverse event reporting system (FAERS) database

Objective

Lumateperone, a novel antipsychotic drug that was granted by the Food and Drug Administration (FDA) approval in December 2019, remains insufficiently explored for its adverse event profile. This study used the FDA Adverse Event Reporting System (FAERS) database to explore its potential safety issues.

Methods

This study conducted a retrospective analysis of FAERS data from the fourth quarter of 2019 to the third quarter of 2023, extracting reports related to lumateperone. Disproportionality analysis using Reporting Odds Ratio (ROR) and Bayesian Confidence Propagation Neural Network (BCPNN) algorithms was employed to detect signals of adverse events (AEs).

Results

Our research processed 4,777 pertinent AE disclosures related to lumateperone, unveiling 125 signals that satisfied both ROR and BCPNN evaluative benchmarks across 26 System Organ Classes (SOCs). Intriguingly, 108 of these signals were categorized as unanticipated, spotlighting notable psychiatric manifestations such as mania (ROR = 73.82, 95% CI = 57.09-95.46; IC = 6.16, IC025 = 4.49), and hypomania (ROR = 34.74, 95% CI = 15.54-77.64; IC = 5.10, IC025 = 3.43), alongside non-psychiatric phenomena like urinary retention (ROR = 3.59, 95% CI = 1.80-7.19; IC = 1.84, IC025 = 0.18) and serotonin syndrome (ROR = 8.69, 95% CI = 4.81-15.72; IC = 3.11, IC025 = 1.45).

Conclusion

This research provides real-world safety data on lumateperone post-marketing and is an important supplement to the information from clinical trial studies. Healthcare professionals should be vigilant for the risk of a manic switch in patients with bipolar depression who are administered lumateperone. More epidemiological studies are needed in the future to explore and further evaluate the risk-benefit issue of lumateperone.

Gut health benefits and associated systemic effects provided by functional components from the fermentation of natural matrices

Recently, the role of the gut microbiota in metabolic health, immunity, behavioral balance, longevity, and intestine comfort has been the object of several studies from scientific communities. They were encouraged by a growing interest from food industries and consumers toward novel fermented ingredients and formulations with powerful biological effects, such as pre, pro, and postbiotic products. Depending on the selected strains, the operating conditions, the addition of suitable reagents or enzymes, the equipment, and the reactor configurations, functional compounds with high bioactivity, such as short-chain fatty acids, gamma-aminobutyric acid, bioactive peptides, and serotonin, can be enhanced and/or produced through fermentation of several vegetable matrices. Otherwise, their formation can also be promoted directly in the gut after the dietary intake of fermented foods: In this case, fermentation will aim to increase the content of precursor substances, such as indigestible fibers, polyphenols, some amino acids, and resistant starch, which can be potentially metabolized by endogenous gut microorganisms and converted in healthy molecules. This review provides an overview of the main functional components currently investigated in literature and the associated gut health benefits. The current state of the art about fermentation technology as a promising functionalization tool to promote the direct or indirect formation of gut-health-enhancing components was deepened, highlighting the importance of optimizing microorganism selection, system setups, and process conditions according to the target compound of interest. The collected data suggested the possibility of gaining novel functional food ingredients or products rich in functional molecules through fermentation without performing additional extraction and purification stages, which are needed when conventional culture broths are used.

Recurrent Serotonin Syndrome After Ketamine-assisted Electroconvulsive Therapy: A Case Report and Review of the Literature

Serotonin (5-HT) syndrome (SS) consists of changes in mental status as well as autonomic and neuromuscular changes. Though not well understood, serotonergic pathways have been implicated in the mechanism of action of electroconvulsive therapy (ECT). Ketamine has been used as an induction agent in ECT and as therapy for treatment-resistant depression. Utilizing a case report and literature review, we explored the underlying serotonergic mechanisms of ECT and ketamine by which a syndrome of serotonin toxicity may be precipitated. We describe the case of a 72-year-old woman who developed recurrent SS on 2 occasions in similar circumstances involving the administration of ketamine for ECT. In our literature review, we found 5 cases in which SS was associated with ECT and 1 case linking ketamine to SS. There is emerging evidence that the mechanism of ECT involves 5-HT1A and 5-HT2A receptors, the same receptors that are involved in SS. ECT can transiently increase the permeability of the blood-brain barrier, leading to increased levels of antidepressants in the brain. ECT can, therefore, enhance 5-HT transmission and the likelihood of SS in the presence of serotonergic agents. The effect of ketamine on 5-HT transmission is mediated by the glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor. Ketamine increases α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid activity in the medial prefrontal cortex, which leads to downstream 5-HT release through glutamate. Through this mechanism, ketamine can increase 5-HT transmission, leading to SS. To our knowledge, this is the only case report of recurrent SS with concurrent use of ECT and ketamine. As ketamine is frequently used in ECT and many patients undergoing ECT are on serotonergic medications, it is important to recognize ketamine as a potential risk factor for SS. There is no evidence for added efficacy when combining ECT and ketamine. Thus, one should proceed with caution when combining these treatments. The burgeoning use of ketamine in ambulatory settings makes it necessary to elucidate the risks, which we discuss further. More research is needed into the mechanisms of ketamine and ECT, specifically how the combination of these treatments influence 5-HT levels.

Alpha-methyltryptamine and 5-(2-methylaminopropyl)-benzofuran (5-MAPB) fatal co-intoxication: case report and review of literature

The scientific literature contains little reliable data regarding new psychoactive substances and designer drugs, making it difficult to assess toxic blood levels and potentially lethal threshold. Here, we report a fatal co-intoxication involving two uncommon drugs ‒ alpha-methyltryptamine (AMT) and 5-(2-methylaminopropyl)-benzofuran (5-MAPB) ‒ combined with exposure to benzodiazepines, ephedrine, and norephedrine. AMT and 5-MAPB were quantified using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC/MS-MS), revealing concentrations of AMT 4690 ng/mL and 5-MAPB 101 ng/mL in postmortem peripheral blood. We additionally reviewed the literature to help interpret the likely roles of these molecules in the occurrence of death.

Effects of Semen Ziziphi Spinosae extract and binary probiotics co-fermentation on the quality of yogurt and their underlying molecular mechanisms

The study aimed to investigate the impact of water-soluble extract from Semen Ziziphi Spinosae (SZSE) on yogurt quality and understand the underlying mechanism. The results demonstrated that adding 0.5% (w/v) SZSE had a significant effect on reducing yogurt syneresis and resulted in a more compact and uniform casein gel. Notably, the co-fermented yogurt with binary probiotics (Lacticaseibacillus casei CGMCC1.5956 and Levilactobacillus brevis CGMCC1.5954) along with SZSE led to increased viable probiotics and a higher odor score (23.23). This effect might be attributed to the increased amino acid utilization by binary probiotics through biosynthesis of valine, leucine and isoleucine, metabolic pathways, and amino acid biosynthesis to produce amino acid derivatives such as N5-(l-1-carboxyethyl)-l-ornithine and diaminopyrimidine acid. The yogurt contained 79 volatile flavor compounds, with hexanoic acid, 2-heptanone, and 2-nonanone potentially contributing to the high odor scores. These findings have strategic implications for developing yogurt with high gel characteristics and distinctive flavor.

The effect of duloxetine on postoperative pain and opium consumption in spine surgery: A systematic review

Background

Postoperative pain after spinal surgery is a major problem that can impact patients' quality of life. Duloxetine is a serotonin and norepinephrine reuptake inhibitor (SNRI) with analgesic effect in different pain disorders. In this study, we aim to evaluate the safety and analgesic effect of duloxetine on acute and chronic pain following spine surgery.

Methods

A systematic search was completed on MEDLINE, PsycINFO, and Embase through OVID from inception to April 2023 to find relevant articles. We used Cochrane methodology to evaluate the bias of included studies. Investigated outcomes included postoperative pain, opioid consumption, and adverse events.

Results

Seven articles involving 487 participants were included in our systematic review. Out of 7 papers, 5 were randomized clinical trials, 1 was a pilot trial and 1 was a retrospective observational study. The results of these studies indicated the analgesic effect of duloxetine on postoperative pain, which was measured using numeric rating scale, verbal numeric scale, brief pain inventory, and visual analogue scale. Duloxetine was generally safe without serious adverse events. The most common reported adverse events included headache, nausea, vomiting, itching, dizziness, and drowsiness.

Conclusions

Duloxetine may be an effective treatment option for postoperative pain following spine surgery, but further rigorously designed and well-controlled randomized trials are required.

''Myth Busting in Infectious Diseases'': A Comprehensive Review

Antibiotics have played a pivotal role in modern medicine, drastically reducing mortality rates associated with bacterial infections. Despite their significant contributions, the emergence of antibiotic resistance has become a formidable challenge, necessitating a re-evaluation of antibiotic use practices. The widespread belief in clinical practice that bactericidal antibiotics are inherently superior to bacteriostatic ones lacks consistent support from evidence in randomized controlled trials (RCTs). With the latest evidence, certain infections have demonstrated equal or even superior efficacy with bacteriostatic agents. Furthermore, within clinical practice, there is a tendency to indiscriminately order urine cultures for febrile patients, even in cases where alternative etiologies might be present. Consequently, upon obtaining a positive urine culture result, patients often receive antimicrobial prescriptions despite the absence of clinical indications warranting such treatment. Furthermore, it is a prevailing notion among physicians that extended durations of antibiotic therapy confer potential benefits and mitigate the emergence of antimicrobial resistance. Contrary to this belief, empirical evidence refutes such assertions. This article aims to address common myths and misconceptions within the field of infectious diseases.

Successful treatment of a severe 5-hydroxytrytophan intoxication using carbon hemoperfusion, hemodiafiltration, and mechanical ventilation in a dog

OBJECTIVE

To describe the successful use of carbon hemoperfusion and hemodiafiltration in combination with mechanical ventilation (MV) to treat a severe intoxication of 5-hydroxytryptophan (5-HTP) in a dog.

CASE SUMMARY

A dog ingested a minimum of 550 mg/kg of extended-release 5-HTP, resulting in serotonin syndrome that progressed to a comatose state and severe hypoventilation requiring MV. Extracorporeal carbon hemoperfusion coupled with hemodiafiltration was performed to remove 5-HTP from this patient. A carbon hemoperfusion cartridge was placed in series upstream in the extracorporeal circuit from the hemodialyzer. A total of 46.5 L of blood (4.89 L/kg) was processed during a 4.85-hour treatment. Serial plasma samples were obtained at 0, 60, 90, and 150 minutes during the session and 14 hours after the session. These samples were later analyzed for 5-HTP and serotonin concentrations. The extraction ratio of 5-HTP was 93.6%-98.9% through the carbon filter. The dog was weaned from MV within 8 hours after extracorporeal therapy and, after a full recovery, was successfully discharged.

NEW OR UNIQUE INFORMATION PROVIDED

Despite an extensive review of the available literature, this appears to be the first reported case of using a carbon hemoperfusion, hemodiafiltration, and MV to treat severe serotonin syndrome secondary to 5-HTP intoxication in a dog. The combination of carbon hemoperfusion and hemodiafiltration can significantly reduce plasma 5-HTP concentrations after acute intoxication and may serve to decrease morbidity and mortality in patients with severe intoxication.

5-hydroxytryphophan mitigates ergot alkaloid-induced suppression of serotonin and feed intake in cattle

The impact of ergot toxicosis on livestock industries is detrimental and treatments are needed in many countries. The objective of this study was to evaluate the effects of acute exposure to ergot alkaloids and 5-hydroxytryptophan (5-HTP) supplementation on feed intake, serotonin metabolism, and blood metabolites in cattle. Eight Holstein steers (538 ± 18 kg) fitted with ruminal cannulas were used in a replicated 4 × 4 Latin Square design experiment with a 2 × 2 factorial treatment structure. The treatments were the combination of 0 (E-) or 15 µg ergovaline/kg BW (E+) and 0 (5HTP-) or 0.5 mg of 5-hydroxy-l-tryptophan/kg BW (5HTP+) administered daily for 6 d. Toxic endophyte-infected tall fescue seed was used to supply the daily dose of ergovaline. Endophyte-free seed was used to equalize seed intake between treatments. Ground seed was placed into the rumen immediately before feeding. The 5-HTP was dissolved in water and infused into the abomasum via the reticulo-omasal orifice. Blood was collected from a jugular vein catheter at 0, 1, 2, 4, 8, and 24 h after treatment administration. Ergovaline without 5-HTP (E+/5HTP-) decreased dry matter intake (DMI) in comparison to steers without ergovaline and 5-HTP (E-/5HTP-). However, 5-HTP infusion in association with ergovaline (E+/5HTP+) normalized the DMI. Although E + did not affect (P > 0.05) the area under the curve (AUC) of serum 5-HTP, 5-hydroxyindoleacetic acid, tryptophan, and kynurenine, serum and plasma serotonin concentrations were decreased (P < 0.05). The infusion of 5-HTP increased (P < 0.05) the AUC of serum 5-HTP, serum and plasma serotonin, and serum 5-hydroxyindoleacetic acid. In conclusion, acute exposure to ergot alkaloids reduced DMI and circulating serotonin in cattle but 5-HTP administration showed potential to normalize both circulating serotonin and feed intake.

Knowledge, Attitude, and Practice of Saudi Medical, Nursing, and Pharmacy Students and Interns Regarding Antidepressant Drugs and Drug-Induced Serotonin Syndrome

Background and aim Antidepressant drugs are commonly used to treat depressive disorders and anxiety. However, they can cause side effects, including drug-induced serotonin syndrome, which is a potentially life-threatening condition. It is essential to understand the level of knowledge of healthcare professionals who are likely to prescribe and administer these medications. This article aims to assess the knowledge of Saudi medical, nursing, and pharmacy students and interns regarding antidepressant drugs and drug-induced serotonin syndrome. Methods A cross-sectional survey was conducted among medical, nursing, and pharmacy students and interns in Saudi Arabia. A self-administered questionnaire was used to collect data from participants. The questionnaire consisted of three sections: demographic information, knowledge about antidepressants, and knowledge about serotonin syndrome. Results A total of 425 participants were included in the study. The median knowledge score for antidepressants and serotonin syndrome was moderate to good, with median scores of 18 out of 23 (IQR: 16-20) and eight out of 12 (IQR: 6-10), respectively. However, more than half of the participants had sufficient knowledge about these topics, with only 227 (53.4%) and 264 (62.1%) having sufficient knowledge about antidepressants and serotonin syndrome, respectively. Regarding serotonin syndrome, males had a significantly higher proportion of sufficient knowledge compared to females, 86 (70.5%) out of 122 vs. 178 (58.7%) out of 303 (p=0.024), respectively. Medical students/interns had a significantly higher proportion of sufficient knowledge about antidepressants compared to nursing students/interns. According to the academic year, interns had the highest proportion of sufficient knowledge. Conclusion The current study revealed that Saudi medical, nursing, and pharmacy students and interns had moderate to good levels of knowledge about antidepressants and serotonin syndrome. The participating students had slightly better knowledge about serotonin syndrome in comparison to knowledge about antidepressants. Further research is needed to identify the causes of the knowledge gap and develop targeted interventions to address these causes. Educational efforts to ensure the safe and effective use of antidepressants are needed.

Serotonin syndrome in the acute treatment landscape of migraine: the lasmiditan experience

Background

Serotonin syndrome (SS) symptoms overlap with adverse events associated with lasmiditan, a 5-HT (serotonin)1F receptor agonist for acute treatment of migraine. Because SS symptoms are heterogeneous, diagnosis can be challenging, and potential cases observed with lasmiditan treatment led to questions about SS pathophysiology. Here, we provide an overview of the potential risk of SS based on experience with lasmiditan.

Methods

Results of eight phase 2 and phase 3 lasmiditan trials (n = 5,916) and a controlled intravenous trial of lasmiditan (n = 88) were analyzed for symptomatology consistent with SS. Post-marketing surveillance data from lasmiditan's US launch date (January 2020) until data cut-off (April 2021) were also examined. Established Sternbach and Hunter diagnostic criteria were used for formal determination of SS.

Results

Of 6,004 lasmiditan-treated clinical trial patients, 15 reported ≥1 treatment-emergent adverse event consistent with signs and symptom(s) of SS. After review, one case met Sternbach and Hunter criteria, two cases potentially met Sternbach criteria, and three cases reported as SS had limited/no information to determine if either criterion was met. During post-marketing surveillance (approximately 13,400 lasmiditan prescriptions), 17 cases with symptom complexes consistent with SS were reported; 3/17 cases had adequate case descriptions to apply predefined criteria. Of these, two met Sternbach and Hunter criteria, and one met Sternbach criteria.

Conclusion

Awareness of clinical symptomatology and diagnostic criteria of SS can help clinicians with recognition of rare instances of SS that may occur with lasmiditan.

Clinical trial registration

NCT03670810, NCT00384774, NCT00883051, NCT02565186.

Serotonin syndrome caused by a CYP2C19-mediated interaction between low-dose escitalopram and clopidogrel: a case report

Background

Serotonin syndrome has been recognized as a serious adverse reaction to antidepressants and is characterized by sudden or severe autonomic nerve dysfunction and neuromuscular symptoms. Without an accurate diagnosis and prompt treatment, serotonin syndrome progresses rapidly and can be life-threatening. It is usually related to the dose of 5-hydroxytryptamine drugs, and the dose is the basis for diagnosis. Therefore, serotonin syndrome induced by low-dose antidepressants rarely occurs, and clinicians are more likely to misdiagnose patients who take low-dose antidepressants with similar symptoms. Here, we present a case study of serotonin syndrome caused by a relatively low dose of escitalopram, which is not common in past references.

Case summary

The patient was a 74-year-old Asian woman with a 42-year history of schizophrenia. After 6 weeks of antidepressant treatment, our patient presented with characteristic myoclonus in the lower limbs and closed eyes with fluttering. Initially, she was misdiagnosed with neuroleptic malignant syndrome (NMS) due to antipsychotic medication and was treated accordingly, even with discontinuation of clozapine. However, her symptoms persisted, and then therapeutic drug monitoring was initiated with the involvement of a clinical pharmacist. Eventually, she was diagnosed with serotonin syndrome due to escitalopram levels reaching the warning level. Subsequently, the patient's treatment was modified, and her clinical outcome was satisfactory without any other serious adverse reactions. Gene detection was also performed, and a cytochrome P450 enzyme (CYP) 2C19-mediated interaction between low-dose escitalopram and clopidogrel seems to be a possible mechanism.

Conclusion

Data on this is extremely scarce, and to the best of our knowledge, serotonin syndrome caused by low-dose antidepressants has not yet been discussed to any great extent in the literature. Our case provides more clinical experience in the treatment of serotonin syndrome.

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.

Challenges in the Clinical Diagnosis of Lithium Toxicity: A Case Report

Lithium, a medication commonly used to treat bipolar disorders, has a narrow therapeutic index, putting patients at risk of lithium toxicity. Such toxicity could entail neurological-related complications and could be precipitated by several factors. In this paper, the authors discuss a case of a middle-aged woman taking lithium for bipolar disorder who presented to the emergency department with altered mental status, tremors, generalized weakness, and dysarthria. Multiple differential diagnoses were considered during her hospitalization, which included an admission to the intensive care unit. This case highlights the variability of lithium toxicity presentations and its management challenges. Further research is needed to understand such manifestations, potential precipitating factors, differential diagnoses, and effective detection and management.

Urinary 5-Hydroxyindolacetic Acid Measurements in Patients with Neuroendocrine Tumor-Related Carcinoid Syndrome: State of the Art

Carcinoid syndrome (CS), mostly associated with small intestinal neuroendocrine tumors (SI-NETs) or lung-related NETs, is characterized by symptoms related to hormonal secretion and long-term complications, including carcinoid heart disease (CHD), which is potentially life-threatening. In the early stages of the disease, symptoms are non-specific, which leads to delayed diagnoses. The availability of reliable tumor markers is crucial for a prompt diagnosis and proper management. This review summarizes available evidence on the role of 24 h urinary 5-hydroxyindolacetic acid (24u5HIAA), which is the urinary breakdown metabolite of serotonin, in the diagnosis/follow-up of NET-related CS, with a focus on its potential prognostic role, while eventually attempting to suggest a timeline for its measurement during the follow-up of NET patients. The use of 24u5HIAA is an established biomarker for the diagnosis of NETs with CS since it shows a sensibility and specificity of 100% and 85-90%, respectively. The downside of 24u5-HIAA is represented by the need for 24 h urine collection and the risk of confounding factors (foods and medication), which might lead to false positive/negative results. Moreover, 24u5HIAA is useful in the follow-up of NETs with CS since a shorter double time correlates to a higher risk of disease progression/disease-specific mortality. Furthermore, an elevation in 24u5-HIAA is correlated with a dismal prognosis because it is associated with an increased likelihood of CHD development and disease progression/mortality. Other potentially interesting biochemical markers have been proposed, including plasmatic 5HIAA, although further standardization and prospective studies are required to define their role in the management of NETs. Meanwhile, 24u5HIAA remains the most accurate CS biomarker.

Serotonin syndrome from combination hydrocodone and cyclobenzaprine in a patient with cerebral palsy

Aim: Serotonin syndrome (SS) is a life-threatening syndrome that occurs with the use of serotonergic drugs, most commonly due to two or more agents. Cerebral palsy is associated with mood disorders, and more commonly pain, with a prevalence of up to 50-80%. Case presentation: A 58-year-old female with cerebral palsy, metastatic malignancy and mood disorder who presented to the emergency department with acute-on-chronic pain, and signs of SS. She was initiated on iv. dilaudid, titrated off oral medications and scheduled for a left-sided sacroiliac joint injection. Results: It was suspected that due to additional doses of hydrocodone and cyclobenzaprine, she developed moderate-SS. Conclusion: Physicians need to be cognizant of comorbidities and uncommon pain medications that can predispose patients to SS.

Cardiogenic Shock Due to Serotonin Syndrome Induced Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy causes transient left ventricular dysfunction. It typically has a favorable prognosis but rarely leads to complications such as cardiogenic shock. Also known as stress-induced cardiomyopathy, it is precipitated by emotional or physical stress. Serotonin syndrome can cause severe stress due to excessive serotonergic activity in the central nervous system. We report a case of cardiogenic shock precipitated by serotonin syndrome-induced takotsubo cardiomyopathy. Only one other documented case has exhibited cardiogenic shock in this setting.

Serotonin Syndrome: The Role of Pharmacology in Understanding Its Occurrence

Serotonin syndrome (SS) is a potentially fatal adverse drug reaction characterized by an exaggerated increase in serotonergic activity in the central and peripheral nervous systems. It presents a constellation of signs and symptoms related to behavioral changes, neuromuscular excitability, and autonomic instability. These symptoms can occur in both mild and severe forms. SS can be triggered by the therapeutic use of a drug that increases serotonin (5-HT) availability in the synaptic cleft or by the co-administration of two or more drugs that provide this increase. With the escalating use of antidepressants by the world's population, this adverse reaction may be more recurrent. However, SS is often overlooked by patients or not diagnosed by doctors. This review aims to improve awareness about SS and provide a pharmacological perspective to explain its occurrence. Evidence shows that other neurotransmitters may also be involved with the pathology of SS. Furthermore, SS and neuroleptic malignant syndrome (NMS) seem to be part of the same pathological spectrum, especially in atypical NMS cases. The emergence of the syndrome's symptoms may be closely related to pharmacokinetic and/or pharmacodynamic polymorphisms that lead to an increase in the 5-HT available to or 5-HT signaling by specific receptors, thus constituting an important area for future investigations.

Sex Difference in Cardioprotection against Acute Myocardial Infarction in MAO-B Knockout Mice In Vivo

The cardiomyocyte-specific knockout (KO) of monoamine oxidase (MAO)-B, an enzyme involved in the formation of reactive oxygen species (ROS), reduced myocardial ischemia/reperfusion (I/R) injury in vitro. Because sex hormones have a strong impact on MAO metabolic pathways, we analyzed the myocardial infarct size (IS) following I/R in female and male MAO-B KO mice in vivo. Method and Results: To induce the deletion of MAO-B, MAO-B KO mice (Myh6 Cre+/MAO-Bfl/fl) and wild-type (WT, Cre-negative MAO-Bfl/fl littermates) were fed with tamoxifen for 2 weeks followed by 10 weeks of normal mice chow. Myocardial infarction (assessed by TTC staining and expressed as a percentage of the area at risk as determined by Evans blue staining)) was induced by 45 min coronary occlusion followed by 120 min of reperfusion. Results: The mortality following I/R was higher in male compared to female mice, with the lowest mortality found in MAO-B KO female mice. IS was significantly higher in male WT mice compared to female WT mice. MAO-B KO reduced IS in male mice but had no further impact on IS in female MAO-B KO mice. Interestingly, there was no difference in the plasma estradiol levels among the groups. Conclusion: The cardiomyocyte-specific knockout of MAO-B protects male mice against acute myocardial infarction but had no effect on the infarct size in female mice.

A Case Report on Serotonin Syndrome in a Patient With Parkinson’s Disease: Diagnostic and Management Challenges

Patients with Parkinson's disease are often at risk of polypharmacy, which can lead to serious medication side effects and interactions. Serotonin syndrome (SS) can develop in this patient population due to a possible drug-drug interaction between antidepressants and antiparkinson drugs with serotoninergic activity. On the other hand, these patients are also at risk of malignant syndrome (MS) secondary to dopaminergic medication withdrawal. In this case report, we present a 71-year-old female with Parkinson's disease who developed symptoms suggestive of SS. The patient was admitted to the medical intensive care unit at the Institute for Pulmonary Diseases of Vojvodina in the Republic of Serbia due to impaired consciousness and a previously witnessed cardiorespiratory arrest. Her chronic antiparkinson medication regimen consisted of levodopa, benserazide, entacapone, ropinirole, and rasagiline. Furthermore, she had been prescribed duloxetine for a remote history of depression, which she had only been taking intermittently. Several days before admission, however, the patient started taking duloxetine again due to low mood. Upon admission, laboratory tests revealed leukocytosis with neutrophilia, elevated C-reactive protein, procalcitonin, lactate, urea, and creatinine. Serum creatine kinase (CK) levels were also elevated at 1250 U/L. Six hours after admission to the ICU, the patient developed hyperthermia, hyperreflexia, spontaneous myoclonus, and tremors. Her CK levels continued to rise, reaching 6900 U/L, and her renal function worsened. Due to the possibility of either SS or MS, external cooling measures with frozen gel packs were administered, resulting in the patient's stabilization over a few hours. Further, serotoninergic medication (rasagiline and duloxetine) was discontinued. On the fifth day of hospitalization, a head CT showed signs of cytotoxic edema. On the 11th day, the patient became hemodynamically unstable and passed away despite all adequate resuscitative measures. The purpose of this case report is to raise awareness of possible SS in patients taking monoamine oxidase-B (MAO-B) inhibitors such as rasagiline. Clinicians should have a high index of suspicion for this complication, especially in patients who are treated for comorbid depression with serotoninergic drugs. Furthermore, we emphasize the importance of correctly differentiating SS from MS, which are both risks for patients with Parkinson's disease. A correct approach to these patients is of utmost importance for adequate management and optimal outcomes.

Potentially harmful drug-drug interactions in the therapeutic regimens of persons with spinal cord injury

OBJECTIVES

Individuals with spinal cord injury deal with multiple health complications that require them to use many medications. The purpose of this paper was to find the most common potentially harmful drug-drug interactions (DDIs) in therapeutic regimens of persons with spinal cord injury, and the risk factors associated with it. We further highlight the relevance of each of the DDIs specific to spinal cord injury population.

DESIGN

Observational design and cross-sectional analysis.

SETTING

Community; Canada.

PARTICIPANTS

Individuals with spinal cord injury (n = 108).

MAIN OUTCOME MEASURES/ANALYSIS

The main outcome was the presence of one or more potential DDIs that can lead to an adverse outcome. All the reported drugs were classified as per the World Health Organization's Anatomical Therapeutic Chemical Classification system. Twenty potential DDIs were selected for the analysis based on the most common medications prescribed to people with spinal cord injury and severity of clinical consequences. The medication lists of study participants were analyzed for selected DDIs.

RESULTS

Among the 20 potential DDIs analyzed in our sample, the top 3 prevalent DDIs were Opioids + Skeletal Muscle Relaxants, Opioids + Gabapentinoids, and Benzodiazepines + ≥ 2 other central nervous system (CNS)-active drugs. Of the total sample of 108 respondents, 31 participants (29%) were identified with having at least one potential DDI. The risk of having a potential DDI was highly associated with polypharmacy, though no associations were found between the presence of a drug interaction and age, sex, level of injury, time since injury, or cause of injury among the study sample.

CONCLUSION

Almost three out of ten individuals with spinal cord injury were at risk of having a potentially harmful drug interaction. Clinical and communication tools are needed that facilitate identification and elimination of harmful drug combinations in the therapeutic regimens of patients with spinal cord injury.

Synthetic Cathinones and Neurotoxicity Risks: A Systematic Review

According to the EU Early Warning System (EWS), synthetic cathinones (SCs) are the second largest new psychoactive substances (NPS) class, with 162 synthetic cathinones monitored by the EU EWS. They have a similar structure to cathinone, principally found in Catha Edulis; they have a phenethylamine related structure but also exhibit amphetamine-like stimulant effects. Illegal laboratories regularly develop new substances and place them on the market. For this reason, during the last decade this class of substances has presented a great challenge for public health and forensic toxicologists. Acting on different systems and with various mechanisms of action, the spectrum of side effects caused by the intake of these drugs of abuse is very broad. To date, most studies have focused on the substances’ cardiac effects, and very few on their associated neurotoxicity. Specifically, synthetic cathinones appear to be involved in different neurological events, including increased alertness, mild agitation, severe psychosis, hyperthermia and death. A systematic literature search in PubMed and Scopus databases according to PRISMA guidelines was performed. A total of 515 studies published from 2005 to 2022 (350 articles from PubMed and 165 from Scopus) were initially screened for eligibility. The papers excluded, according to the criteria described in the Method Section (n = 401) and after full text analyses (n = 82), were 483 in total. The remaining 76 were included in the present review, as they met fully the inclusion criteria. The present work provides a comprehensive review on neurotoxic mechanisms of synthetic cathinones highlighting intoxication cases and fatalities in humans, as well as the toxic effects on animals (in particular rats, mice and zebrafish larvae). The reviewed studies showed brain-related adverse effects, including encephalopathy, coma and convulsions, and sympathomimetic and hallucinogenic toxidromes, together with the risk of developing excited/agitated delirium syndrome and serotonin syndrome.

Fatal Intoxications from a Combination of 4-Fluoroamphetamine and 25C-NBOMe

Six fatalities have occurred from the ingestion of a combination of new psychoactive substances (NPSs), 4-fluoroamphetamine (4FA) and 2-(4-chloro-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25C-NBOMe) over a 9-month period. Four of these fatalities (one older female and three young males) were from direct adverse effects of drugs, and one each from a fall while being intoxicated and during restraint. All cases were subject to full postmortem examinations that included collection of femoral blood. The four drug-caused fatalities had postmortem blood concentrations for 4FA and 25C-NBOMe of 330-682 ng/L (median 417) and 1.4-12 ng/mL (median 4.3), respectively. The other two cases (both young males) where death was considered to have been caused indirectly by drug intoxication had 4FA and 25C-NBOMe postmortem concentrations of 21 and 123 ng/mL, and 1.8 and 4.5 ng/mL, respectively. None of these cases showed concentrations of drugs that suggested use of high recreational doses. In one drug-caused death, capsules and a brown powder obtained from the scene were found to contain a mixture of these two NPSs. With the exception of one drug-caused death, other drugs were detected; however, the effects of the two NPSs together were regarded as the primary triggers for the deaths. There were no consistent symptoms or pathology in these cases; however, agitation/aggression was observed in two cases prior to their collapse, with seizures in possibly three cases. Pulmonary and/or cerebral edema was noted in three cases. Potentially significant natural disease (a mildly enlarged heart) was only observed in one drug-caused case. These cases illustrate a possible increased risk of sudden death with this combination of drugs, both of which can elevate serotonin concentrations as well as act as strong stimulants. These cases also illustrate the difficulty in detecting NPS in cases where no prior information is available that might suggest their use.

Off-target activity of NBOMes and NBOMe analogs at the µ opioid receptor

New psychoactive substances (NPS) are introduced on the illicit drug market at a rapid pace. Their molecular targets are often inadequately elucidated, which contributes to the delayed characterization of their pharmacological effects. Inspired by earlier findings, this study set out to investigate the µ opioid receptor (MOR) activation potential of a large set of psychedelics, substances which typically activate the serotonin (5-HT_2A) receptor as their target receptor. We observed that some substances carrying the N-benzyl phenethylamine (NBOMe) structure activated MOR, as confirmed by both the NanoBiT® βarr2 recruitment assay and the G protein-based AequoScreen® Ca²⁺ release assay. The use of two orthogonal systems proved beneficial as some aspecific, receptor independent effects were found for various analogs when using the Ca²⁺ release assay. The specific 'off-target' effects at MOR could be blocked by the opioid antagonist naloxone, suggesting that these NBOMes occupy the same common opioid binding pocket as conventional opioids. This was corroborated by molecular docking, which revealed the plausibility of multiple interactions of 25I-NBOMe with MOR, similar to those observed for opioids. Additionally, structure-activity relationship findings seen in vitro were rationalized in silico for two 25I-NBOMe isomers. Overall, as MOR activity of these psychedelics was only noticed at high concentrations, we consider it unlikely that for the tested compounds there will be a relevant opioid toxicity in vivo at physiologically relevant concentrations. However, small modifications to the original NBOMe structure may result in a panel of more efficacious and potent MOR agonists, potentially exhibiting a dual MOR/5-HT_2A activation potential.

Jitteriness/anxiety syndrome caused by coadministration of celecoxib, a selective COX-2 inhibitor, with escitalopram and trazodone in a patient with depression and spondylolisthesis

Antidepressant-induced jitteriness/anxiety syndrome is characterized as anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia, and (hypo)mania, which appear immediately after initiation or increased dosage of an antidepressant. This report describes a case of the jitteriness/anxiety syndrome caused by the coadministration of celecoxib with escitalopram and trazodone in a patient with depression and spondylolisthesis. The depression of a patient, a woman in her 60 s, had been in remission at least for 5 years under treatment using escitalopram and trazodone. Immediately after coadministration of celecoxib because of her buttock and limb pain, she showed anxiety, agitation, akathisia, insomnia, irritability, aggressiveness, impulsivity, and hypomania. These symptoms disappeared after the discontinuation of celecoxib. The present case suggests that coadministration of celecoxib with escitalopram and trazodone can cause the jitteriness/anxiety syndrome, presumably via a pharmacokinetic interaction of celecoxib with these antidepressants and/or the effects of celecoxib on serotonergic neurotransmission.

The Effect of the Stress Induced by Hydrogen Peroxide and Corticosterone on Tryptophan Metabolism, Using Human Neuroblastoma Cell Line (SH-SY5Y)

L-tryptophan (L-Trp) is an important amino acid in several physiological mechanisms, being metabolized into two important pathways: the kynurenine and the serotonin (5-HT) pathways. It is important in processes such as mood and stress response, the 5-HT pathway begins with the conversion of L-Trp to 5-hydroxytryptophan (5-HTP), that is metabolized into 5-HT, converted to melatonin or to 5-hydroxyindoleacetic acid (5-HIAA). Disturbances in this pathway are reported to be connected with oxidative stress and glucocorticoid-induced stress, are important to explore. Thus, our study aimed to understand the role of hydrogen peroxide (H₂O₂) and corticosterone (CORT)-induced stress on the serotonergic pathway of L-Trp metabolism, and on SH-SY5Y cells, focusing on the study of L-Trp, 5-HTP, 5-HT, and 5-HIAA in combination with H₂O₂ or CORT. We evaluated the effect of these combinations on cellular viability, morphology, and on the extracellular levels of the metabolites. The data obtained highlighted the different ways that stress induction led to different extracellular medium concentration of the studied metabolites. These distinct chemical transformations did not lead to differences in cell morphology/viability. Additionally, serotonin may be the most sensitive metabolite to the exposure to the different stress inducers, being more promissory to study conditions associated with cellular stress.

Remission of treatment-resistant obsessive-compulsive disorder with 600 milligrams of fluvoxamine daily: a case report

First-line drugs for obsessive-compulsive disorder (OCD) pharmacotherapy are selective serotonin reuptake inhibitors (SSRI). The medication must be continued for at least 12 weeks at an effective dosage to find the most effective SSRI. For treatment, the drug dose should be titrated to the highest tolerated dose. The manufacturer's recommended maximum dose of fluvoxamine is 300 mg per day. We reported remission after about 1 month of 600 mg (high dose) fluvoxamine, which was tolerated by a patient with OCD. The patient continued at this dose for 3 months and remained in remission.

Utilization patterns, cardiovascular risk, and concomitant serotoninergic medications among triptan users between 2008 and 2018: A gender analysis in one Italian region, Tuscany

OBJECTIVE

To describe the pattern of triptan use by gender in Tuscany, Italy, focusing on special user populations in which evidence on triptan safety is still not conclusive.

BACKGROUND

Growing evidence supports the role of gender differences in migraine pathophysiology and treatment. However, gender impact on triptan real-word utilization has been poorly investigated.

METHODS

A retrospective, descriptive, cohort study was performed using the population-based Administrative Healthcare Database of Tuscany region (Italy). Subjects registered in the database on the January 1 of each year between 2008 and 2018 were identified. New users (NU) of triptans (ATC:N02CC*) were patients with one or more triptan dispensation during the year of interest and none in the past. Age, cardiovascular comorbidities representing an absolute or a possible contraindication to triptan utilization, concomitant serotonergic medications, and pattern of triptan use during 1-year follow-up were described by gender.

RESULTS

A total of 86,109 patients who received one or more triptan dispensing were identified. Of 64,672 NU (men = 17,039; women = 47,633), 10.2% (6823/64,672) were aged >65 years, who were mostly women (n = 4613). Among NU, men and women with absolute cardiovascular contraindications were 4.3% (740/17,039) and 2.1% (1022/47,633), respectively, while those concomitantly taking serotonergic medications were 17.2% (267/1549) and 21.9% (949/4330), respectively (949/4330). Regular users (two or more dispensing with ≥3 months between first and last observed dispensing) accounted for 26.4% of women (12,597/47,633) and 19.11% of men (3250/17,039); frequent users (≥15 dosage units/month during ≥3 consecutive months) were overall 0.1% (94/64,672) and 62.0% (58/94) of them concomitantly received serotonergic medications.

CONCLUSION

Considering gender differences in triptan use highlighted here, large scale observational studies are warranted to better define what populations are safe to use triptans and whether it is appropriate to tighten or relax certain recommendations on triptan use. In the meantime, any suspected adverse drug reaction observed in the special user populations highlighted in this study should be promptly reported.

Tapentadol: A Review of Experimental Pharmacology Studies, Clinical Trials, and Recent Findings

Tapentadol is an analgesic compound that acts centrally to attenuate pain. Previous studies have shown that tapentadol has dual mechanisms of action as a mu-opioid receptor agonist and noradrenaline re-uptake inhibition. Therefore, tapentadol provides a great advantage over classic opioids in pain management from nociceptive to neuropathic. Cumulative evidence from in vitro data suggests that tapentadol effect of norepinephrine re-uptake could be a new target that overcomes other classic opioids in chronic neuropathic pain. Compared to tramadol and other opioids, tapentadol is associated with fewer adverse effects than tramadol. Tapentadol is a new alternative to treat acute, chronic, and neuropathic pain. Thus, this review article was focused on understanding the studies that led to the development of tapentadol as a novel analgesic drug and its advantages over conventional opioids. Thus, tapentadol is a good alternative with fewer adverse effects and is available for human use.

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.

Microbiome-Related Indole and Serotonin Metabolites are Linked to Inflammation and Psychiatric Symptoms in People Living with HIV

Background:

People living with HIV (PLHIV) exhibit dysregulation of tryptophan metabolism. Altered gut microbiome composition in PLHIV might be involved. Mechanistic consequences within the 3 major tryptophan metabolism pathways (serotonin, kynurenine, and indoles), and functional consequences for platelet, immune and behavioral functions are unknown. We investigated plasma tryptophan metabolites, gut microbiome composition, and their association with platelet function, inflammation, and psychiatric symptoms.

Methods:

This study included 211 PLHIV on long-term antiretroviral treatment (ART). Plasma tryptophan pathway metabolites were measured using time-of-flight mass spectrometry. Bacterial composition was profiled using metagenomic sequencing. Platelet reactivity and serotonin levels were quantified by flowcytometry and ELISA, respectively. Circulating inflammatory markers were determined using ELISA. Symptoms of depression and impulsivity were measured by DASS-42 and BIS-11 self-report questionnaires, respectively.

Results:

Plasma serotonin and indole metabolites were associated with gut bacterial composition. Notably, species enriched in PLHIV were associated with 3-methyldioxyindole. Platelet serotonin concentrations were elevated in PLHIV, without effects on platelet reactivity. Plasma serotonin and indole metabolites were positively associated with plasma IL-10 and TNF-α concentrations. Finally, higher tryptophan, serotonin, and indole metabolites were associated with lower depression and anxiety, whereas higher kynurenine metabolites were associated with increased impulsivity.

Conclusion:

Our results suggest that gut bacterial composition and dysbiosis in PLHIV on ART contribute to tryptophan metabolism, which may have clinical consequences for immune function and behavior.

The regulatory role of AP-2β in monoaminergic neurotransmitter systems: insights on its signalling pathway, linked disorders and theragnostic potential

Monoaminergic neurotransmitter systems play a central role in neuronal function and behaviour. Dysregulation of these systems gives rise to neuropsychiatric and neurodegenerative disorders with high prevalence and societal burden, collectively termed monoamine neurotransmitter disorders (MNDs). Despite extensive research, the transcriptional regulation of monoaminergic neurotransmitter systems is not fully explored. Interestingly, certain drugs that act on these systems have been shown to modulate central levels of the transcription factor AP-2 beta (AP-2β, gene: TFAP2Β). AP-2β regulates multiple key genes within these systems and thereby its levels correlate with monoamine neurotransmitters measures; yet, its signalling pathways are not well understood. Moreover, although dysregulation of TFAP2Β has been associated with MNDs, the underlying mechanisms for these associations remain elusive. In this context, this review addresses AP-2β, considering its basic structural aspects, regulation and signalling pathways in the controlling of monoaminergic neurotransmitter systems, and possible mechanisms underpinning associated MNDS. It also underscores the significance of AP-2β as a potential diagnostic biomarker and its potential and limitations as a therapeutic target for specific MNDs as well as possible pharmaceutical interventions for targeting it. In essence, this review emphasizes the role of AP-2β as a key regulator of the monoaminergic neurotransmitter systems and its importance for understanding the pathogenesis and improving the management of MNDs.

Cutting the First Turf to Heal Post-SSRI Sexual Dysfunction: A Male Retrospective Cohort Study

Post-SSRI sexual dysfunction (PSSD) is a set of heterogeneous sexual problems, which may arise during the administration of selective serotonin reuptake inhibitors (SSRIs) and persist after their discontinuation. PSSD is a rare clinical entity, and it is commonly associated with non-sexual concerns, including emotional and cognitive problems and poor quality of life. To date, however, no effective treatment is available. The aim of this study was to retrospectively evaluate the potential efficacy of the different treatments used in clinical practice in improving male PSSD. Of the 30 patients referred to our neurobehavioral outpatient clinic from January 2020 to December 2021, 13 Caucasian male patients (mean age 29.53 ± 4.57 years), previously treated with SSRIs, were included in the study. Patients with major depressive disorder and/or psychotic symptoms were excluded a priori to avoid overlapping symptomatology, and potentially reduce the misdiagnosis rate. To treat PSSD, we decided to use drugs positively affecting the brain dopamine/serotonin ratio, such as bupropion and vortioxetine, as well as other compounds. This latter drug is known not to cause or reverse iatrogenic SD. Most patients, after treatment with vortioxetine and/or nutraceuticals, reported a significant improvement in all International Index of Erectile Function-(IIEF-5) domains (p < 0.05) from baseline (T0) to 12-month follow-up (T1). Moreover, the only patient treated with pelvic muscle vibration reached very positive results. Although our data come from a retrospective open-label study with a small sample size, drugs positively modulating the central nervous system serotonin/dopamine ratio, such as vortioxetine, could be used to potentially improve PSSD. Large-sample prospective cohort studies and randomized clinical trials are needed to investigate the real prevalence of this clinical entity and confirm such a promising approach to a potentially debilitating illness.

Serotonin syndrome induced by overdose of atomoxetine alone in a patient with attention-deficit hyperactivity disorder: A case report

Background

Serotonin syndrome is characterized by mental status changes, autonomic hyperactivity, and neuromuscular abnormalities. This syndrome results from various medications that engender serotonergic overactivity. Atomoxetine is a norepinephrine reuptake inhibitor used for the treatment of attention-deficit hyperactivity disorder (ADHD). Two case reports have described serotonin syndrome induced by the combination of atomoxetine with venlafaxine or methylphenidate, but no report describes this syndrome induced by atomoxetine alone. This report describes serotonin syndrome induced solely by an overdose of atomoxetine in a patient with ADHD.

Case Presentation

The patient in this case was a 21-year-old man who had been treated with atomoxetine for ADHD. He was transported to our hospital 1 h after intentional ingestion of 1200 mg of atomoxetine in a suicide attempt. On admission, he showed profuse diaphoresis, marked agitation, somnolence, slight fever, tachycardia, prolonged QT interval, myoclonus, tremor, and hyperreflexia. He was diagnosed as having serotonin syndrome and was treated with administration of activated charcoal and massive infusion. Three days later, his serotonin syndrome symptoms had disappeared completely.

Conclusion

Findings in this case suggest that atomoxetine alone can cause serotonin syndrome presumably via its effects of serotonin reuptake inhibition. Clinicians should consider this syndrome induced by atomoxetine overdose.

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.

Real-time monitoring of serotonin with highly selective aptamer-functionalized conducting polymer nanohybrids

Adequate serotonin levels are pivotal to human well-being; thus, serotonin can be used as a biomarker because it regulates a wide range of physical and psychological functions. As an imbalance of serotonin is highly likely to initiate the pathogenesis of various disorders, monitoring serotonin levels in real time is in high demand for the early detection of disease. We fabricated a field-effect transistor (FET) biosensor based on aptamer-immobilized conducting polymer nanohybrids, which showed an instantaneous response toward serotonin in solution. The mechanism of serotonin detection was based on aptamer deformation after aptamer-ligand interaction and the consequential decrease in the charge carrier density of the FET template. Docking simulations with AutoDock/Vina and PyMOL were successfully used to investigate the binding site of serotonin in the loop structure of the aptamer. The fabricated FET template showed high sensitivity toward serotonin in the range of 10 fM to 100 nM, and the limit of detection (LOD) was exceptionally low at 10 fM. Moreover, the selectivity toward serotonin was confirmed by observing no signal after the injection of structural analogs, functional analogs and excess physiological biomolecules. The potential clinical application of this sensor was confirmed because it remained consistent when the buffer solution was exchanged for artificial serum or artificial cerebrospinal fluid (CSF). ^† S.G.L. and S.E.S. contributed equally to this work.

Antidepressant-induced serotonin syndrome in older patients: a cross-sectional study

BACKGROUND

Widespread prescription of antidepressants and their resulting role in serotonin syndrome (SS) are of great importance for clinical practice in the elderly. This study aims to investigate possible associations of antidepressant drug-induced SS with related variables in these patients.

METHODS

A total of 238 older adults using antidepressants were included. Patients who fulfilled the Hunter Serotonin Toxicity Criteria (HSTC) for SS were considered as the clinical groups (mild, moderate, or severe), and those who did not as the control group. We recorded all patients' demographic and clinical characteristics, including age, gender, comorbidity index, number of medications, daily equivalent dose of the relevant antidepressant according to fluoxetine per day, electrocardiogram test results, laboratory results, and management.

RESULTS

The mean age of all patients was 75.4 ± 7.6 years and 63.4% were female. Sixty patients had SS, while 178 patients did not. There was a significant difference between those with and without SS in terms of gender, frequency of combination antidepressant therapy, and daily equivalent antidepressant dose (P < 0.05). The most common diagnostic findings in SS patients were tremor and hyperreflexia and 31.7% was mild, and moderate in 68.3% with higher median age and number of medications (P < 0.041). Antidepressants were discontinued in all patients regardless of severity, of whom 71.7% were treated with benzodiazepines and 36.7% with cyproheptadine. After adjusting for age and sex, association with use of SSRI + SNRI, use of any combination therapy, and daily equivalent dose remained significant.

CONCLUSIONS

The widespread single or combined use of antidepressants in older adults represents an increased clinical concern for SS and physicians should be aware of this drug-related complication in older patients.

MDMA for the Treatment of Negative Symptoms in Schizophrenia

The profound economic burden of schizophrenia is due, in part, to the negative symptoms of the disease, which can severely limit daily functioning. There is much debate in the field regarding their measurement and classification and there are no FDA-approved treatments for negative symptoms despite an abundance of research. 3,4-Methylenedioxy methamphetamine (MDMA) is a schedule I substance that has emerged as a novel therapeutic given its ability to enhance social interactions, generate empathy, and induce a state of metaplasticity in the brain. This review provides a rationale for the use of MDMA in the treatment of negative symptoms by reviewing the literature on negative symptoms, their treatment, MDMA, and MDMA-assisted therapy. It reviews recent evidence that supports the safe and potentially effective use of MDMA to treat negative symptoms and concludes with considerations regarding safety and possible mechanisms of action.

Current research in pathophysiology of opioid induced respiratory depression

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In Oprm1-deleted KO mice, both the preBötC and the KF/PBN are major contributors to OIRD but RD is not totally eliminated.

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PreBötC neurons expressing NK-1R are necessary for breathing. Their deletion results in ataxic breathing and/or apnoea.

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GIRK channels are involved in inhibiting respiration by mu opioid receptors. KCNQ channels modulate OIRD independent of mu signaling.

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Morphine depresses normal but not gasping breathing in rats indicating distinct mechanisms for these 2 forms of breathing.

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Methadone, given to alleviate symptoms of neonatal opioid withdrawal syndrome, desensitizes rats to respiratory depression.

Respiratory depression (RD) is the primary cause of death due to opioids. Opioids bind to mu (µ)-opioid receptors (MORs) encoded by the MOR gene Oprm1, widely expressed in the central and peripheral nervous systems including centers that modulate breathing. Respiratory centers are located throughout the brainstem. Experiments with Oprm1-deleted knockout (KO) mice undertaken to determine which sites are necessary for the induction of opioid-induced respiratory depression (OIRD) showed that the pre-Bötzinger complex (preBötC) and the pontine Kölliker-Fuse nucleus (KF) contribute equally to OIRD but RD was not totally eliminated. Morphine showed a differential influence on preBötC and KF neurons – low doses attenuated RD following deletion of MORs from preBötC neurons and an increase in apneas after high doses whereas deletion of MORs from KF neurons but not the preBötC attenuated RD at both high and low doses. In other KO mice studies, morphine administration after deletion of Oprm1 from both the preBötC and the KF/PBN neurons, led to the conclusion that both respiratory centres contribute to OIRD but the preBötC predominates. MOR-mediated post-synaptic activation of GIRK potassium channels has been implicated as a cause of OIRD. A complementary mechanism in the preBötC involving KCNQ potassium channels independent of MOR signaling has been described. Recent experiments in rats showing that morphine depresses normal, but not gasping breathing, cast doubt on the belief that eupnea, sighs, and gasps, are under the control of preBötC neurons. Methadone, administered to alleviate symptoms of neonatal opioid withdrawal syndrome (NOWES), desensitized rats to OIRD. Protection lost between postnatal days 1 and 2 coincides with the preBötC becoming the dominant generator of respiratory rhythm. Neonatal antidepressant exposure syndrome (NADES) and serotonin toxicity (ST) show similarities including RD. Enzyme CYP2D6 involved in opioid detoxification is polymorphic. Individuals of different CYP2D6 genotype may show increased, decreased, or no enzyme activity, contributing to the variability of patient responses to different opioids and OIRD.

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.

Opioid Drug-Drug-Drug Interactions and Unintentional Traumatic Injury: Screening to Detect Three-Way Drug Interaction Signals

Growing evidence suggests that drug interactions may be responsible for much of the known association between opioid use and unintentional traumatic injury. While prior research has focused on pairwise drug interactions, the role of higher-order (i.e., drug-drug-drug) interactions (3DIs) has not been examined. We aimed to identify signals of opioid 3DIs with commonly co-dispensed medications leading to unintentional traumatic injury, using semi-automated high-throughput screening of US commercial health insurance data. We conducted bi-directional, self-controlled case series studies using 2000-2015 Optum Data Mart database. Rates of unintentional traumatic injury were examined in individuals dispensed opioid-precipitant base pairs during time exposed vs unexposed to a candidate interacting precipitant. Underlying cohorts consisted of 16-90-year-olds with new use of opioid-precipitant base pairs and ≥1 injury during observation periods. We used conditional Poisson regression to estimate rate ratios adjusted for time-varying confounders, and semi-Bayes shrinkage to address multiple estimation. For hydrocodone, tramadol, and oxycodone (the most commonly used opioids), we examined 16,024, 8185, and 9330 drug triplets, respectively. Among these, 75 (0.5%; hydrocodone), 57 (0.7%; tramadol), and 42 (0.5%; oxycodone) were significantly positively associated with unintentional traumatic injury (50 unique base precipitants, 34 unique candidate precipitants) and therefore deemed potential 3DI signals. The signals found in this study provide valuable foundations for future research into opioid 3DIs, generating hypotheses to motivate crucially needed etiologic investigations. Further, this study applies a novel approach for 3DI signal detection using pharmacoepidemiologic screening of health insurance data, which could have broad applicability across drug classes and databases.

An Update on the Implications of New Psychoactive Substances in Public Health

The emergence of new psychoactive substances has earned a great deal of attention, and several reports of acute poisoning and deaths have been issued involving, for instance, synthetic opiates. In recent years, there have been profound alterations in the legislation concerning consumption, marketing, and synthesis of these compounds; rapid alert systems have also been subject to changes, and new substances and new markets, mainly through the internet, have appeared. Their effects and how they originate in consumers are still mostly unknown, primarily in what concerns chronic toxicity. This review intends to provide a detailed description of these substances from the point of view of consumption, toxicokinetics, and health consequences, including case reports on intoxications in order to help researchers and public health agents working daily in this area.

Side Effects of Amino Acid Supplements

The aim of the article is to examine side effects of increased dietary intake of amino acids, which are commonly used as a dietary supplement. In addition to toxicity, mutagenicity and carcinogenicity, attention is focused on renal and gastrointestinal tract functions, ammonia production, and consequences of a competition with other amino acids for a carrier at the cell membranes and enzymes responsible for their degradation. In alphabetic order are examined arginine, β-alanine, branched-chain amino acids, carnosine, citrulline, creatine, glutamine, histidine, β-hydroxy-β-methylbutyrate, leucine, and tryptophan. In the article is shown that enhanced intake of most amino acid supplements may not be risk-free and can cause a number of detrimental side effects. Further research is necessary to elucidate effects of high doses and long-term consumption of amino acid supplements on immune system, brain function, muscle protein balance, synthesis of toxic metabolites, and tumor growth and examine their suitability under certain circumstances. These include elderly, childhood, pregnancy, nursing a baby, and medical condition, such as diabetes and liver disease. Studies are also needed to examine adaptive response to a long-term intake of any substance and consequences of discontinuation of supplementation.