Selective serotonin reuptake inhibitor poisoning: An evidence-based consensus guideline for out-of-hospital management

Comparison of clinicodemographic characteristics in patients with selective serotonin reuptake inhibitors poisoning: A cross-sectional study

Background

Our objective of this study was to evaluate patients of Selective Serotonin Reuptake Inhibitors (SSRIs) overdose and compare the toxicological effects of citalopram overdose with other SSRIs in adult poisoning cases.

Methods

This cross-sectional study focused on acute, known-type SSRI ingestions. Demographic and toxicological data were collected on the patients. The outcomes analyzed were length of hospital stay, coma, seizures, electrocardiographic abnormalities, abnormal heart examination, and the presence of serotonin syndrome.

Results

There were a total of 199 cases, with 165 (82.9%) being women. The majority of cases (n = 76, 38.2%) were attributed to citalopram, followed by sertraline (n = 67, 33.7%), fluoxetine (n = 33, 16.6%), fluvoxamine (n = 10, 5%), escitalopram (n = 6, 3%), paroxetine (n = 1, 0.5%), and mixed (n = 6, 3%). The most common symptoms were nausea and vomiting (n = 96, 48.2%). Most patients (58.3%) were conscious, with only 7 patients (3.5%) experiencing seizures. Among those with seizures, six patients had taken citalopram, with 50% of them ingesting 400 mg of citalopram. Tachycardia was observed in 62 (31.2%) patients, while no QT interval prolongation, PR interval changes, or arrhythmias were reported. Serotonin toxicity was noted in only 6 patients (3%), with 4 of them being poisoned with citalopram. The incidence of seizures with citalopram was significantly higher than with other SSRIs (odds ratio (OR) = 10.457; 1.6-2.88, P = 0.008), while nausea and vomiting were significantly more common in poisoning cases involving other SSRIs (OR = 0.51; 0.2-0.9, P = 0.02). There were no reported deaths.

Conclusion

Ingesting SSRIs results in minimal toxicity. However, seizures are more likely to occur with citalopram compared to other SSRIs.

Unexpectedly Prolonged Serotonin Syndrome and Fatal Complications Following a Massive Overdose of Paroxetine Controlled-Release

Symptoms caused by a selective serotonin reuptake inhibitor (SSRI) overdose are often mild and can be managed with supportive care and close monitoring, even when complicated by serotonin syndrome. There are limited pharmacokinetic data regarding massive overdoses of paroxetine, and the severity of an SSRI overdose is likely to be underestimated. We describe a fatal case of severe serotonin syndrome and acute respiratory distress syndrome (ARDS) following an overdose of controlled-release paroxetine. A 53-year-old male with depression presented with altered consciousness. He had ingested controlled-release paroxetine along with other medications. On arrival, he had ocular flutter and myoclonus, and blood examinations revealed acute kidney injury and rhabdomyolysis, which suggested serotonin syndrome. Computed tomography (CT) showed pharmacobezoars in the esophagus and stomach. Symptoms of serotonin syndrome and hypotension persisted despite administration of high doses of vasopressors with endotracheal intubation. We performed endoscopic decontamination to remove pharmacobezoars from the stomach. Finally, he developed severe ARDS and died due to respiratory failure on day 23. Sequential serum concentrations of paroxetine were 5.38 µg/mL at admission and 3.21 µg/mL on day 7, both above lethal levels. This case highlights the potential for fatal complications and prolonged toxicity in the case of a massive overdose of controlled-release paroxetine. We should recognize that such an overdose may be life-threatening and should consider aggressive interventions including endoscopic decontamination. A better understanding of the pharmacokinetics of a massive SSRI overdose would be helpful for optimal management.

Connecting Mind-Body Therapy-Mediated Effects to Pathological Features of Alzheimer's Disease

Alzheimer's disease (AD) is a complex, multifactorial neurodegenerative disorder that represents a major and increasing global health challenge. In most cases, the first clinical symptoms of AD are preceded by neuropathological changes in the brain that develop years to decades before their onset. Therefore, research in the last years has focused on this preclinical stage of AD trying to discover intervention strategies that might, if implemented effectively, delay or prevent disease progression. Among those strategies, mind-body therapies such as yoga and meditation have gained increasing interest as complementary alternative interventions. Several studies have reported a positive impact of yoga and meditation on brain health in both healthy older adults and dementia patients. However, the underlying neurobiological mechanisms contributing to these effects are currently not known in detail. More specifically, it is not known whether yogic interventions, directly or indirectly, can modulate risk factors or pathological mechanisms involved in the development of dementia. In this article, we first review the literature on the effects of yogic practices on outcomes such as cognitive functioning and neuropsychiatric symptoms in patients with mild cognitive impairment and dementia. Then, we analyze how yogic interventions affect different risk factors as well as aspects of AD pathophysiology based on observations of studies in healthy individuals or subjects with other conditions than dementia. Finally, we integrate this evidence and propose possible mechanisms that might explain the positive effects of yogic interventions in cognitively impaired individuals.

Toxicology of Psychoactive Substances

A trend in the increasing use of prescription psychoactive drugs (PADs), including antidepressants, antipsychotics, and mood stabilizers, has been reported in the United States and globally. In addition, there has been an increase in the production and usage of illicit PADs and emergence of new psychoactive substances (NPSs) all over the world. PADs pose unique challenges for critical care providers who may encounter toxicology issues due to drug interactions, side effects, or drug overdoses. This article provides a summary of the toxicologic features of commonly used and abused PADs: antidepressants, antipsychotics, mood stabilizers, hallucinogens, NPSs, caffeine, nicotine, and cannabis.

Distribution of Fluvoxamine and Identification of the Main Metabolite in a Fatal Intoxication

Fluvoxamine is a selective serotonin reuptake inhibitor, with a half-life of about 30 hours, that is commonly prescribed in the treatment of depression and obsessive and compulsive disorders. Though its more favorable adverse effect profile in comparison to tricyclic antidepressants, overdosages could lead to severe central nervous system depression. We hereby report the case of a 48-year-old woman with psychiatric disorders, who died in the Protected Community where she lived. An autopsy, during which multiorgan congestion and aspiration of gastric content were found, was performed 9 days after the death. Femoral and cardiac blood, urine and bile were collected for toxicological analysis. GC-MS, LC-MS-MS and LC-HRMS screenings were performed on blood samples. The analysis allowed to identify the following drugs: fluvoxamine, clotiapine, 7-aminoclonazepam, propranolol, gabapentin and haloperidol. Quantification of the detected drugs in blood was performed by means of a validated LC-MS-MS analytical procedure, and the following results were achieved: fluvoxamine (2.20 mg/L), gabapentin (41.00 mg/L), 7-aminoclonazepam (0.24 mg/L), clotiapine (0.07 mg/L), haloperidol (<0.01 mg/L) and propranolol (0.24 mg/L). Fluvoxamine concentration in blood exceeded ~10 times the upper limit of therapeutic blood levels (0.23 mg/L). Contributory causes of death, such as due to multiple drug use, however, cannot be excluded. The distribution of fluvoxamine in all biological fluids was evaluated and a postmortem redistribution effect was observed (C/P blood ratio: 1.86). Fluvoxamine acid metabolite was identified in urine, bile and in cardiac blood, through an LC-QTOF analytical procedure.

Movement Disorder Emergencies

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

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

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

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

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

Poison-related visits in a pediatric emergency department: A retrospective analysis of patients who bypass poison control centers

INTRODUCTION

Poison control centers (PCC) are an effective means to prevent unnecessary emergency department (ED) visits associated with poisoning exposures. However, not all patients with poison exposures utilize the PCC. The purpose of this study was to identify unintentional pediatric poisoning exposures presenting to a large US children's hospital that could have been managed onsite (i.e., at home) if consultation with a PCC had occurred prior to the ED visit.

METHODS

Using ED encounters from a tertiary children's hospital, unintentional pharmaceutical, chemical, or fume exposures occurring between October 1, 2014 and September 30, 2015 were identified from ICD-9-CM billing codes. Two specialists in poison information reviewed the medical records of the identified patients who had no contact with the PCC and determined whether these encounters were preventable through PCC triage. Descriptive statistics examined the differences between the encounters. Data were analyzed in R v3.2.4 (Vienna, Austria) and SAS v9.4 (SAS Institute, Cary, NC).

RESULTS

In the total study population (n = 231), 98 (42.4%) were PCC triaged and 133 (57.6%) were caregiver self-referred to the ED. For those who self-referred, 62 (46.6%) patients would have been recommended to be managed onsite instead of presenting at the ED for medical care. Analgesics and household cleaning products were the most common pharmaceutical and chemical exposures, respectively.

CONCLUSIONS

Nearly half of ED visits for pediatric patients with unintentional poisoning exposures could have been avoided by contacting a PCC. Educational and self-efficacy-based interventions are needed to expand the public's use of PCC services.

Characterization of intentional-abuse venlafaxine exposures reported to poison control centers in the United States

Background: Venlafaxine use to achieve an amphetamine-like high has been described but data regarding the epidemiology and clinical effects are sparse. Objectives: Describe the prevalence and toxicity of venlafaxine abuse reported to US poison control centers. Methods: This was a retrospective review of venlafaxine exposures reported to the National Poison Data System (NPDS) from 2000 to 2016. Inclusion criteria were: age 12 years and older, reason for exposure intentional-abuse, and either single-substance exposure or venlafaxine was the first substance. The primary outcome was prevalence of intentional-abuse of venlafaxine. Secondary outcomes characterized demographics, geographic distribution, toxicity, and outcomes. Results: Intentional-abuse accounted for 752 of 85,621 venlafaxine exposures. Overall prevalence was 87.8 intentional-abuse exposures/10,000 venlafaxine exposures reported to NPDS (range, 59.3-117.6/10,000). Prevalence decreased from 107/10,000 in 2000 to 59.3/10,000 in 2016. Median age was 23 years and 50% were female. Primary route was ingestion (90.8%) with 4.7% using venlafaxine via inhalation/intranasal insufflation, and 3.7% both routes. There were 227 venlafaxine-only exposures; 54.0% were treated/released from the emergency department, 20% were admitted for medical management, 9.0% to a psychiatric facility, and 17.0% managed at home. Known medical outcomes for single-substance exposures were: no effect (24.0%), minor (39.0%), moderate (33.0%), and major (4.0%); no deaths occurred. Most frequent clinical effects were tachycardia (33.9%), drowsiness (20.7%), and agitation (11.5%). Conclusion: The prevalence of venlafaxine abuse reported to poison control centers has decreased. Medical outcomes are usually not serious. Clinicians should be aware that non-medical use is possible but infrequently reported to poison control centers.

Serotonin Syndrome in a Pediatric Patient After Vilazodone Ingestion

Serotonin syndrome (SS) is a serious toxicity that manifests with symptoms such as tremor, hyperthermia, agitation, and altered mental status that may lead to seizures, coma, or death. Selective serotonin reuptake inhibitors may precipitate SS, particularly in combination with other drugs that possess serotonergic activity. We present a case of SS in a 14-month-old after an ingestion of the selective serotonin reuptake inhibitor vilazodone.

Drug-Induced Serotonin Syndrome

Serotonin syndrome is a potentially fatal condition caused by drugs that affect serotonin metabolism or act as serotonin receptor agonists. Monoamine oxidase inhibitors, selective serotonin reuptake inhibitors, and serotonin-norepinephrine reuptake inhibitors are the medications most commonly associated with serotonin syndrome. Serotonin syndrome can be mild and of short duration, but a prolonged course, life-threatening complications, and death are possible. Detection of serotonin syndrome is not difficult if the diagnostic criteria are understood and properly used, but the syndrome has no confirmatory tests and other drug-induced syndromes can, to a degree, mimic serotonin syndrome. The treatment is symptomatic and supportive. Antidotal therapies are available, but the evidence for their effectiveness is limited. If serotonin syndrome is promptly identified and aggressively treated, the patient should fully recover.

Delayed Serotonin Syndrome in the Setting of a Mixed Fluoxetine and Serotonin Antagonist Overdose

BACKGROUND Serotonin syndrome is a condition characterized predominantly by neuromuscular symptoms and altered thermoregulation in response to serotonergic overtone. Treatment is focused on withdrawal of serotonergic agents, which leads to resolution in the majority of cases. In the setting of serotonergic overdose, the onset of serotonin syndrome is usually within 4 to 13 h. Here, we report a case of delayed-onset serotonin syndrome in a patient who ingested a mixture of longer-acting serotonin agonists with serotonin antagonists. CASE REPORT A 24-year-old male was transferred to our medical intensive care unit with hypotension and altered mental status after an overdose of fluoxetine, cyproheptadine, trazodone, olanzapine, risperidone, and bupropion. After approximately 72 h, the patient developed symptoms of fever, lower leg clonus, hyperreflexia, and agitation. He was diagnosed with delayed-onset serotonin syndrome, which responded well to re-administration of cyproheptadine, leading to resolution of symptoms by day 5 of his stay. CONCLUSIONS In this present case, our patient presented with the longest reported delay in the onset of serotonin syndrome after intentional ingestion. This was likely secondary to co-ingestion of long-acting serotonin agonists with protective shorter-acting serotonin antagonists (cyproheptadine and olanzapine). Clinicians should consider delayed-onset serotonin syndrome when patients ingest longer-acting serotonergic agents with serotonin antagonists.

Negative myoclonus secondary to paroxetine intake

Outside the context of overdose and serotonin syndrome, seizures and myoclonic movements attributed to selective serotonin reuptake inhibitors (SSRIs) are rare and poorly documented. We present a 77-year-old man, with no history of epilepsy, presenting in the emergency department with whole body jerks since that morning. Two days earlier, due to a prescription mistake, he was started on paroxetine 20 mg instead of his usual fluoxetine 20 mg. The patient's electroencephalogram (EEG), performed in the emergency department, revealed a bilateral synchronous parieto-occipital fast spike activity pattern, which correlated consistently with negative myoclonus. Two days after stopping paroxetine, the patient presented no seizures and no abnormalities in the EEG. We present an EEG documented case of drug-induced seizures, with a bilateral parieto-occipital pattern, secondary to paroxetine intake. A hyperexcitability of the primary somatosensory cortex inhibiting primary motor cortex output could explain the electroclinical correlation.

Antidepressants are cytotoxic to rat primary blood brain barrier endothelial cells at high therapeutic concentrations

Antidepressants are commonly employed for the treatment of major depressive disorders and other psychiatric conditions. We investigated the relatively acute cytotoxic effects of three commonly prescribed antidepressants: fluoxetine, sertraline, and clomipramine on rat primary blood brain barrier endothelial cells over a concentration range of 0.1-100μM. At therapeutic concentrations (0.1μM) no significant cytotoxicity was observed after 4, 24, or 48h. At high therapeutic to overdose concentrations (1-100μM), antidepressants reduced cell viability in proportion to their concentration and exposure duration. At 1μM, antidepressants significantly reduced mitochondrial membrane potential. At drug concentrations producing ~50% inhibition of cell viability, all drugs significantly reduced cellular oxygen consumption rates, activities of mitochondrial complexes I and III, and triggered a significant increase of lactate production. Fluoxetine (6.5μM) and clomipramine (5.5μM) also significantly lowered transcellular transport of albumin. The mechanism of cellular cytotoxicity was evaluated and at high concentrations all drugs significantly increased the production of reactive oxygen species, and significantly increased the activity of the pro-apoptotic caspases-3, 8, and 9. Comet assays revealed that all drugs were genotoxic. Pre-incubation of cells with glutathione significantly ameliorated antidepressant-induced cytotoxicity, indicating the potential benefit of treatment of overdosed patients with antioxidants.

webPOISONCONTROL: can poison control be automated?

BACKGROUND

A free webPOISONCONTROL app allows the public to determine the appropriate triage of poison ingestions without calling poison control. If accepted and safe, this alternative expands access to reliable poison control services to those who prefer the Internet over the telephone. This study assesses feasibility, safety, and user-acceptance of automated online triage of asymptomatic, nonsuicidal poison ingestion cases.

METHODS

The user provides substance name, amount, age, and weight in an automated online tool or downloadable app, and is given a specific triage recommendation to stay home, go to the emergency department, or call poison control for further guidance. Safety was determined by assessing outcomes of consecutive home-triaged cases with follow-up and by confirming the correct application of algorithms. Case completion times and user perceptions of speed and ease of use were measures of user-acceptance.

RESULTS

Of 9256 cases, 73.3% were triaged to home, 2.1% to an emergency department, and 24.5% directed to call poison control. Children younger than 6 years were involved in 75.2% of cases. Automated follow-up was done in 31.2% of home-triaged cases; 82.3% of these had no effect. No major or fatal outcomes were reported. More than 91% of survey respondents found the tool quick and easy to use. Median case completion time was 4.1 minutes.

CONCLUSION

webPOISONCONTROL augments traditional poison control services by providing automated, accurate online access to case-specific triage and first aid guidance for poison ingestions. It is safe, quick, and easy to use.

High Prevalence of Psychotropics Overdose among Suicide Attempters in Korea

Objective

The availability of suicide methods affects the risk of suicide attempts. This study examined the patterns of substances ingested by suicide attempters (SAs) and the characteristics of SAs using psychotropic overdoses.

Methods

Data for 384 of the 462 eligible SAs who used self-poisoning were analyzed. Demographic variables, clinical characteristics, and factors related to the suicide attempts were examined.

Results

There were 256 (66.7%) females and 128 (33.3%) males. Roughly half the SAs ingested psychotropics (n=179, 46.6%). Agricultural chemicals (n=84, 21.9%) were the second most frequently ingested substances, followed by analgesics (n=62, 16.1%), household products (n=27, 7.0%), and other prescribed medications (n=23, 6.0%). Among psychotropics, the most frequently overdosed drugs were sedative-hypnotics, including hypnotics (n=104) and benzodiazepines (n=78). SAs favored Z-drugs and alprazolam. When compared with SAs with non-psychotropic overdoses, significantly more SAs with psychotropic overdoses were female (76% vs. 58.5%, p<0.001) and had a psychiatric history (59.8% vs. 29.8%, p<0.001). They had significantly more previous suicide attempts (0.52±1.02 vs. 0.32±0.80, p<0.05) and lower risk (7.96±1.49 vs. 8.44±1.99, p<0.01) and medical severity (3.06±0.81 vs. 3.37±0.93, p<0.005) scores.

Conclusion

Psychotropic overdose, especially with sedative-hypnotics, was a major method in suicide attempts. It is important that psychiatric patients are carefully evaluated and monitored for suicidality when prescribing psychotropics.

Mechanisms and environmental factors that underlying the intensification of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy)-induced serotonin syndrome in rats

RATIONALE

Illicit use of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) may cause a mild or severe form of the serotonin syndrome. The syndrome intensity is not just influenced by drug doses but also by environmental factors.

OBJECTIVES

Warm environmental temperatures and physical activity are features of raves. The purpose of this study was to assess how these two factors can potentially intensify the syndrome.

METHODS

Rats were administered MDMA at doses of 0.3, 1, or 3 mg/kg and examined in the absence or presence of warm temperature and physical activity. The syndrome intensity was estimated by visual scoring for behavioral syndrome and also instrumentally measuring changes in symptoms of the syndrome.

RESULTS

Our results showed that MDMA at 3 mg/kg, but not 0.3 or 1 mg/kg, caused a mild serotonin syndrome in rats. Each environmental factor alone moderately intensified the syndrome. When the two factors were combined, the intensification became more severe than each factor alone highlighting a synergistic effect. This intensification was blocked by the 5-HT2A receptor antagonist M100907, competitive N-methyl-D-aspartic acid (NMDA) receptor antagonist CGS19755, autonomic ganglionic blocker hexamethonium, and the benzodiazepine-GABAA receptor agonist midazolam but not by the 5-HT1A receptor antagonist WAY100635 or nicotinic receptor antagonist methyllycaconitine.

CONCLUSIONS

Our data suggest that, in the absence of environmental factors, the MDMA-induced syndrome is mainly mediated through the serotonergic transmission (5-hydroxytryptamine (5HT)-dependent mechanism) and therefore is relatively mild. Warm temperature and physical activity facilitate serotonergic and other neural systems such as glutamatergic and autonomic transmissions, resulting in intensification of the syndrome (non-5HT mechanisms).

A retrospective review of the prehospital use of activated charcoal

OBJECTIVE

We studied the complications and timing implications of prehospital activated charcoal (PAC). Appropriateness of PAC administration was also evaluated.

METHODS

We retrospectively reviewed prehospital records over 32 months for overdose cases, where PAC was administered. Cases were assessed for amount and type of ingestant, clinical findings, timing of PAC, timing of transport and arrival into the emergency department (ED), and complications. Encounter duration in cases of PAC was compared with that, for all cases during the study period, where an overdose patient who did not receive activated charcoal was transported.

RESULTS

Two thousand eight hundred forty-five total cases were identified. In 441 cases, PAC was given; and complications could be assessed. Two hundred eighty-one of these had complete information regarding timing of ingestion, activated charcoal administration, and transport. The average time between overdose and PAC was 49.8 minutes (range, 7-199 minutes; median, 41.0 minutes; SD, 30.4 minutes). Complications included emesis (7%), declining mental status (4%), declining blood pressure (0.4%), and declining oxygen saturation (0.4%). Four hundred seventeen cases of PAC had documentation of timing of emergency medical service (EMS) arrival on scene and arrival at the ED. Average EMS encounter time was 29 minutes (range, 10-53 minutes; median, 27.9 minutes). Two thousand forty-four poisoning patients were transported who did not receive PAC. The average EMS encounter time for this group was 28.1 minutes (range, 4-82 minutes; median, 27.3 minutes), not significantly different (P =.114).

CONCLUSIONS

Prehospital activated charcoal did not appear to markedly delay transport or arrival of overdose patients into the ED and was generally safe.

Do serotonin reuptake inhibitors worsen outcome of patients referred to the emergency department for deliberate multi-drug exposure?

Incidence of poisonings with serotonin reuptake inhibitors (SRIs) is growing. SRI toxicity is considered low, but its actual impact in multi-drug poisonings remains unclear. Our objective was to evaluate the consequences of SRI exposure in patients referred to the emergency department (ED) for deliberate multi-drug exposure. Patients admitted for multi-drug exposure involving at least one SRI were matched with patients who did not ingest any SRI, according to age, gender, type of drug and ingested doses. Features of serotonin syndrome according to Sternbach's criteria and Hunter's serotonin toxicity criteria were evaluated from records. In 4 years, 148 SRI-exposed patients were included and compared to 296 matched controls. The SRIs mainly involved were escitalopram (22%), venlafaxine (20%), fluoxetine (19%), citalopram (15%) and paroxetine (11%). Serotonin syndrome was diagnosed in one patient, but actually occurred in five SRI-exposed patients based on the retrospective evaluation of records. Twenty patients (14%) exhibited one or more serotonin syndrome criteria. At least two of 11 of Sternbach's criteria and two of nine of Hunter's serotonin toxicity criteria were missing in each chart. Using a conditional logistic regression analysis, seizures (p = 0.04) and serotonin syndrome (p = 0.01 based on Sternbach's criteria and p = 0.004 based on Hunter's serotonin toxicity criteria) more frequently occurred in SRI-exposed patients. Requirement for mechanical ventilation was significantly increased (p = 0.03), although admission to the intensive care unit was not. In multi-drug-poisoned patients admitted to the ED, exposure to SRIs significantly increases the risk of seizures and requirement for mechanically ventilation. Diagnosis of serotonin syndrome remains insufficient justifying improved training.

Selective serotonin reuptake inhibitor exposure

Many antidepressants inhibit serotonin or norepinephrine reuptake or both to achieve their clinical effect. The selective serotonin reuptake inhibitor class of antidepressants (SSRIs) includes citalopram, escitalopram (active enantiomer of citalopram), fluoxetine, fluvoxamine, paroxetine, and sertraline. The SSRIs are as effective as tricyclic antidepressants in treatment of major depression with less significant side effects. As a result, they have become the largest class of medications prescribed to humans for depression. They are also used to treat obsessive-compulsive disorder, panic disorders, alcoholism, obesity, migraines, and chronic pain. An SSRI (fluoxetine) has been approved for veterinary use in treatment of canine separation anxiety. SSRIs act specifically on synaptic serotonin concentrations by blocking its reuptake in the presynapse and increasing levels in the presynaptic membrane. Clinical signs of SSRI overdose result from excessive amounts of serotonin in the central nervous system. These signs include nausea, vomiting, mydriasis, hypersalivation, and hyperthermia. Clinical signs are dose dependent and higher dosages may result in the serotonin syndrome that manifests itself as ataxia, tremors, muscle rigidity, hyperthermia, diarrhea, and seizures. Current studies reveal no increase in appearance of any specific clinical signs of serotonin toxicity with regard to any SSRI medication. In people, citalopram has been reported to have an increased risk of electrocardiographic abnormalities. Diagnosis of SSRI poisoning is based on history, clinical signs, and response to therapy. No single clinical test is currently available to confirm SSRI toxicosis. The goals of treatment in this intoxication are to support the animal, prevent further absorption of the drug, support the central nervous system, control hyperthermia, and halt any seizure activity. The relative safety of the SSRIs in overdose despite the occurrence of serotonin syndrome makes them more desirable than other antidepressants. The prognosis in animals that receive treatment is excellent. In one retrospective study, there were no deaths in 313 SSRI-poisoned dogs. No characteristic or classic histopathologic lesions result from SSRI toxicosis. Differential diagnoses for SSRI overdose must include ingestions of other serotonergic medications such as phenylpiperidine opioids (fentanyl and tramadol), mirtazapine, buspirone, amitraz, and chlorpheniramine.

Changes in intensity of serotonin syndrome caused by adverse interaction between monoamine oxidase inhibitors and serotonin reuptake blockers

Drug interaction between inhibitors of monoamine oxidase (MAOIs) and selective serotonin (5-hydroxytryptamine, 5-HT) reuptake (SSRIs) induces serotonin syndrome, which is usually mild but occasionally severe in intensity. However, little is known about neural mechanisms responsible for the syndrome induction and intensification. In this study, we hypothesized that the syndrome induction and intensity utilize two different but inter-related mechanisms. Serotonin syndrome is elicited by excessive 5-HT in the brain (presynaptic mechanism), whereas syndrome intensity is attributed to neural circuits involving 5-HT2A and NMDA receptors (postsynaptic mechanism). To test this hypothesis, basal 5-HT efflux and postsynaptic circuits were pharmacologically altered in rats by once daily pretreatment of the MAOI clorgyline for 3, 6, or 13 days. Syndrome intensity was estimated by measuring 5-HT efflux, neuromuscular activity, and body-core temperature in response to challenge injection of clorgyline combined with the SSRI paroxetine. Results showed that the onset of serotonin syndrome is caused by 5-HT efflux exceeding 10-fold above baseline, confirming the presynaptic hypothesis. The neuromuscular and body-core temperature abnormalities, which were otherwise mild in drug-naive rats, were significantly intensified to a severe level in rats pretreated with daily clorgyline for 3 and 6 days but not in rats pretreated for 13 days. The intensified effect was blocked by M100907 and MK-801, suggesting that variation in syndrome intensity was mediated through a 5-HT2A and NMDA receptor-engaged circuit. Therefore, we concluded that pretreatments of MAOI pharmacologically alter the activity of postsynaptic circuits, which is responsible for changes in syndrome intensity.

Refractory status epilepticus, circulatory collapse after cardiac arrest, and acute respiratory distress syndrome caused by severe isolated fluvoxamine poisoning: a case report

Case

A 30-year-old female ingested 21.75 g fluvoxamine in a suicide attempt. She presented with grand mal seizures and vomiting on admission to our Emergency Center, with a fluvoxamine serum concentration of 4.58 μg/mL. The patient was diagnosed with status epilepticus, which could not be fully suppressed with the maximum dosage of benzodiazepines. The patient also developed circulatory collapse after resuscitation for sudden cardiac arrest and acute respiratory distress syndrome, believed to be secondary to aspiration.

Outcome

With venoarterial extracorporeal membrane oxygenation, a massive infusion of propofol successfully suppressed status epilepticus, and both the circulatory collapse and acute respiratory distress syndrome gradually improved; venoarterial extracorporeal membrane oxygenation and propofol treatments were then terminated, and the patient was discharged without further disabilities.

Conclusion

Compared to all other reported clinical cases of fluvoxamine poisoning, the patient in this study ingested the highest dose and developed the most severe symptoms, but was successfully treated without any disabilities.

Neurotoxic emergencies

This article is intended for clinicians treating neurotoxic emergencies. Presented are causative agents of neurotoxic emergencies, many of which are easily mistaken for acute psychiatric disorders. Understanding the wide variety of agents responsible for neurotoxic emergencies and the neurotransmitter interactions involved will help the psychiatrist identify and treat this challenging population.

Metabolic and toxicological considerations for obsessive-compulsive disorder drug therapy

INTRODUCTION

Obsessive-compulsive disorder (OCD) affects the daily life of the patients. Chronic nature of this disease and the need for long-term high-dose drug therapy for its maintenance increase the risk of metabolic and toxicological complications.

AREAS COVERED

In this concise article, the metabolic and toxicological aspects of major medication categories prescribed in OCD, such as serotonin-specific reuptake inhibitors, tricyclic antidepressant (clomipramine), serotonin-norepinephrine reuptake inhibitors, and atypical antipsychotics indicated in OCD (both Food and Drug Administration-approved and off-label) are discussed.

EXPERT OPINION

The most critical point in pharmacotherapy of OCD is the need for the high-dose and long-term use of drugs. In OCD, generally the higher doses of applicable drugs than those used in depression are required, often exceeding the recommended maximum dose. Moreover, such high doses should be given for at least 10 - 12 weeks to ensure the adequate treatment duration for the clinical effects to emerge. This long-term high-dose maintenance therapy increases the risk of drug toxicity and adverse effects. Physicians should take extra care in periodical assessment of signs and symptoms of metabolic and toxicological complications in patients. Subjective symptoms reported by patients should be carefully assessed and not attributed to obsessive nature of the patients.

Retrospective evaluation of toxicosis from selective serotonin reuptake inhibitor antidepressants: 313 dogs (2005-2010)

OBJECTIVE

To evaluate a clinical population of dogs exposed to selective serotonin reuptake inhibitor (SSRI) antidepressant medications and describe the clinical findings, epidemiological characteristics, outcome, and prognosis.

DESIGN

Retrospective study (February 1, 2005-August 31, 2010).

SETTING

Animal poison control helpline.

ANIMALS

Three hundred thirteen dogs with presumed SSRI toxicosis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Dogs with presumptive SSRI medication toxicosis identified by a review of the electronic database of Pet Poison Helpline, an animal poison control center, were evaluated. No clinical signs were reported in 76.3% (239/313) of cases. The remaining 23.6% (74/313) of cases demonstrated the following clinical signs: neurological 79.7% (59/74), gastrointestinal 25.6% (19/74), cardiovascular 9.5% (7/74), respiratory 8.2% (6/74), and thermoregulatory 6.7% (5/74). Of the dogs exhibiting neurological signs, 62.7% (37/59) showed depression, 37.2% (22/59) showed hyperactivity, 10.1% (6/59) exhibited ataxia, and 1.7% (1/59) showed other miscellaneous signs (eg, hyperesthesia). There was a significant difference between the dose ingested by symptomatic and asymptomatic dogs for fluoxetine (P = 0.0039), but not with any other SSRI. Ninety-four patients were confirmed to have received veterinary care. In cases where duration of veterinary care was determined (55/313), 67.2% (37/55) of dogs were hospitalized and 32.7% (18/55) treated as outpatients. The average duration of hospitalization was 18.5 hours, excluding outpatient visits. Of those patients that had complete follow-up information available (136/313), overall survival was 100%.

CONCLUSIONS

The overall prognosis for animals with SSRI toxicosis is excellent with veterinary attention. Central nervous system depression was the most common clinical sign associated with SSRI toxicosis.

Recognition and management of perioperative serotonin syndrome

Mild forms of serotonin syndrome can potentially be fatal, if not recognized. The increased use of serotonergic agents makes the awareness of its prevalence, various presentations, diagnostic evaluation, and treatment a clinical imperative. It is important to note that serotonin syndrome can only be diagnosed clinically in the presence of 3 clinical criteria: mental status changes, autonomic manifestations, and neuromuscular abnormalities. This case report describes a patient who underwent an uncomplicated closed nasal fracture reduction and subsequently developed serotonin syndrome.

Low-dose escitalopram for 2 days associated with corrected QT interval prolongation in a middle-aged woman: a case report and literature review

Prolongation of the corrected QT interval (QTc) on the electrocardiography is an important clinical condition because it increases the risk of torsade de pointes, a medical emergency that can cause sudden cardiac death. QTc prolongation can be induced by many drugs, including antipsychotics and tricyclic antidepressants (TCAs). Compared with TCAs, use of selective serotonin reuptake inhibitors (SSRIs) was less likely to cause severe cardiac adverse effects. Escitalopram, one of the SSRIs, has shown significant antidepressant efficacy and well tolerability. Here, we present one female patient showing QTc prolongation induced by low-dose (5 mg/day) treatment of escitalopram for 2 days. The QTc returned to normal soon after discontinuation of escitalopram. Clinicians should be cautious about cardiac effects when using a SSRI, even in a low dose.

Metabolic acidosis and generalized seizures secondary to citalopram overdose: a case report

Selective serotonin re-uptake inhibitors (SSRIs) are widely used in the community for treating many forms of mental illnesses. Citalopram, a newer generation SSRI, is commonly prescribed, but despite its low toxicity profile has a potential to cause seizures and dysarrythmias in overdose. Data on citalopram overdose-induced metabolic acidosis are scarce. There have been only three cases of metabolic acidosis reported in the literature due to citalopram overdose in humans and we are reporting the fourth one. We report a case of citalopram overdose with metabolic acidosis and generalized seizure. To our best knowledge, this is the first case reported in Saudi Arabia.

Compliance with atypical antipsychotic triage guidelines by Texas poison centers

Triage guidelines for poison center management of atypical antipsychotic ingestions were published in December 2007. This investigation determined whether Texas poison centers already complied with a simplified version of these guidelines. All acute aripiprazole, clozapine, olanzapine, quetiapine, risperidone, and ziprasidone ingestions reported to Texas poison centers during 2000-2007 were identified. Exclusion criteria were the presence of coingestants, patient already at or en route to a health-care facility when the poison center was contacted, and chronic ingestion. Each case was evaluated whether it was managed in compliance with the simplified triage guidelines and the compliance rate calculated. For 2,611 total cases, the compliance rate was 64.1%. The rate was 71.7% for aripiprazole, 43.6% for clozapine, 71.6% for olanzapine, 60.8% for quetiapine, 65.5% for risperidone, and 59.0% for ziprasidone. The majority of acute atypical antipsychotic ingestions reported to Texas poison centers were managed according to a simplified version of recommended triage algorithm.

Role of serotonin via 5-HT2B receptors in the reinforcing effects of MDMA in mice

The amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) reverses dopamine and serotonin transporters to produce efflux of dopamine and serotonin, respectively, in regions of the brain that have been implicated in reward. However, the role of serotonin/dopamine interactions in the behavioral effects of MDMA remains unclear. We previously showed that MDMA-induced locomotion, serotonin and dopamine release are 5-HT_2B receptor-dependent. The aim of the present study was to determine the contribution of serotonin and 5-HT_2B receptors to the reinforcing properties of MDMA.

We show here that 5-HT_2B^−/− mice do not exhibit behavioral sensitization or conditioned place preference following MDMA (10 mg/kg) injections. In addition, MDMA-induced reinstatement of conditioned place preference after extinction and locomotor sensitization development are each abolished by a 5-HT_2B receptor antagonist (RS127445) in wild type mice. Accordingly, MDMA-induced dopamine D1 receptor-dependent phosphorylation of extracellular regulated kinase in nucleus accumbens is abolished in mice lacking functional 5-HT_2B receptors. Nevertheless, high doses (30 mg/kg) of MDMA induce dopamine-dependent but serotonin and 5-HT_2B receptor-independent behavioral effects.

These results underpin the importance of 5-HT_2B receptors in the reinforcing properties of MDMA and illustrate the importance of dose-dependent effects of MDMA on serotonin/dopamine interactions.

Comparison of Immediate-Release and Controlled-Release Paroxetine Ingestions Reported to Texas Poison Control Centers between 2002 and 2008

Background:

Controlled-release (CR) paroxetine was created to improve the tolerability of immediate-release (IR) paroxetine while maintaining therapeutic benefits. There is limited information comparing the toxicity of the 2 paroxetine formulations.

Objective:

To compare the toxicity and management of paroxetine IR and paroxetine CR ingestions reported to poison control centers.

Methods:

Cases of ingestion of paroxetine that were reported to Texas poison control centers between 2002 and 2008, in which the final medical outcome and dose were known, were retrospectively reviewed. The rates for selected variables were determined for paroxetine IR and paroxetine CR and comparisons between the 2 were made by calculating the ratio of the drug's CR rate to the IR rate and 95% confidence interval. Compliance with simplified algorithms of triage management guidelines was determined for both formulations.

Results:

Included in the analysis were 405 cases of paroxetine IR ingestion and 169 cases of paroxetine CR ingestion for which a reported dose and final medical outcome were known. There were no statistically significant differences between the paroxetine CR and paroxetine IR formulations with respect to serious medical outcomes (ratio 0.69, 95% CI 0.34 to 1.31), self-harm or malicious intent (ratio 0.82, 95% CI 0.60 to 1.12), or referral to a healthcare facility (ratio 1.18, 95% CI 0.76 to 1.83). The rate of compliance with the triage algorithm for cases not already en route to or at a healthcare facility when the poison control center was contacted was 87% for paroxetine IR and 89% for paroxetine CR.

Conclusions:

The toxicity and management of paroxetine IR and paroxetine CR ingestions reported to Texas poison control centers were similar after adjusting for differences in dosage.

Neonatal fluoxetine exposure affects the neuronal structure in the somatosensory cortex and somatosensory-related behaviors in adolescent rats

Selective serotonin reuptake inhibitor (SSRI)-type antidepressants are often prescribed to depressive pregnant women for their less adverse side effects. However, growing evidences have shown increased congenital malformations and poor neonatal adaptation in the perinatal SSRI-exposed human infants as well as animal pups. In this study, we examined the effects of early exposure of fluoxetine, the most popular SSRI-type antidepressant, on the developing somatosensory system. Physiological saline or fluoxetine (10 mg/kg) was subcutaneously injected into neonatal rats from P0 to P6. Somatosensory-related behaviors were examined in adolescence (P30-P35). Morphological features of the primary somatosensory cortex were checked at P7 and P35. The tactile and thermal perceptions as well as locomotor activity were affected by neonatal fluoxetine treatment. At the morphological level, the number of branch tips of thalamocortical afferents to the somatosensory cortex was reduced in the fluoxetine-treated rats. Furthermore, the spiny stellate neurons in the layer IV somatosensory cortex had reduced dendritic span and complexity with fewer branches, shorter dendritic length, and smaller dendritic field. The spine density of spiny stellate neurons was significantly reduced whereas the spine length of mushroom- and branched-type was increased. Taken together, these results indicate that neonatal fluoxetine administration has long-lasting effects on the function and structure in the somatosensory system. Sensory information processing may be disturbed in the neonatal fluoxetine-treated animals due to the structural deformation in the thalamocortical afferents and dendritic structures of the spiny stellate neurons in the layer IV somatosensory cortex.

Citalopram overdose: late presentation of torsades de pointes (TdP) with cardiac arrest

INTRODUCTION

Citalopram overdose may produce bradycardia, QT prolongation, and torsades de pointes (TdP). A cardiotoxic metabolite may be responsible for the delayed onset of cardiotoxicity. Although some authorities recommend a minimum of 24 hours of observation following citalopram overdose, a recent analysis suggested that dysrhythmias rarely occur beyond 13 hours post-ingestion. We present a case of citalopram overdose with a substantially delayed onset of cardiac toxicity.

CASE REPORT

A 36-year-old woman complained of shakiness, numbness in the arms, and palpitations that began approximately 32 hours after ingesting 50 (20-mg) tablets of citalopram. Her initial vital signs were: blood pressure, 84/44 mmHg; pulse, 102-150/minute; respirations, 17/min; temperature, 99.3 degrees F (37.3 degrees C). Her initial ECG showed sinus rhythm with a prolonged corrected QT interval (572 msec) with paroxysmal, self-limited runs of wide-complex tachycardia that appeared multifocal in nature. Approximately 20 minutes after presentation, she experienced self-terminating TdP, with transient hypotension and loss of consciousness. Her serum citalopram concentration (33 hours post-ingestion) was 477 ng/mL (therapeutic: 40-110 ng/mL); desmethylcitalopram concentration was 123.2 ng/mL (therapeutic: 14-40 ng/mL). She was treated with magnesium and lidocaine, and her corrected QT interval remained abnormal for 24 hours after presentation.

DISCUSSION

Citalopram overdose can produce life-threatening cardiac toxicity with a clinical onset that may be delayed beyond a routine observation period of 6 hours. Once the QT interval is prolonged, it seems prudent to prolong the observation period.