Acute trazodone poisoning: clinical signs and plasma concentrations

Vilazodone poisoning: a systematic review

Introduction: Vilazodone is a novel antidepressant approved for the treatment of major depressive disorder. It acts as a serotonin reuptake inhibitor and 5-HT1A partial agonist. It may lead to a more rapid rise in serotonin concentration in the synaptic cleft than selective serotonin reuptake inhibitors (SSRIs), which could potentially cause more severe toxicity in overdose.Methods: We performed a systematic review of the medical literature to identify all available peer reviewed evidence regarding vilazodone poisoning.Results: We identified nine unique articles describing vilazodone poisoning. These included eleven unique case reports of vilazodone poisoning, three reviews of data from the National Poison Data System, and one review of data from the Toxicology Investigators Consortium. Children were frequently symptomatic, and many developed seizures and/or serotonin syndrome. Adults and adolescents also developed serotonin syndrome after single-substance ingestion of vilazodone. ICU admission, endotracheal intubation, and parenteral benodiazepines were frequently required.Discussion: Vilazodone, unlike SSRIs, may frequently cause serotonin syndrome in single-substance ingestions. Children ingesting as little as the minimum daily dose of vilazodone, 10 mg, suffered major clinical toxicity.Conclusion: Vilazodone poisoning may produce serious clinical effects, including serotonin syndrome and seizures. Young children are at particularly high risk and may become critically ill after ingestion of very small amounts of vilazodone. Admission of poisoned children to a monitored setting and prolonged clinical observation of poisoned adults may be reasonable.

Unintentional trazodone overdoses in children ≤6 years of age: data from poison center over a period of 16 years

CONTEXT

Trazodone is an atypical antidepressant with no established safety in children. Previous case reports showed no complications at doses 50-500 mg in children. Our study objective is to characterize the clinical effects, dose-related toxicity, and establish triage dose for acute trazodone ingestions in children ≤6 years of age.

METHODS

Cases with acute trazodone ingestions in children ≤6 years of age between 2000 and 2015 were retrospectively reviewed. Data were analyzed for dose (mg/kg), clinical effects, management site, treatment, and outcome. Cases with coingestions, unknown outcome, or unknown dose were excluded.

RESULTS

A total of 84 patients (mean age 26.7 months, 35 females, 49 males) were included. Of those, 52 (61.9%) had no clinical effects; 29 (34.5%) had minor effects (vomiting, dizziness, headache); and three (3.6%) had moderate effects (ataxia, slurred speech, priapism). No major effects or deaths were observed. Moderate effects were manifested at doses ≥6.9 mg/kg. Priapism occurred in a 2-year-old child at a dose of 6.9 mg/kg. Sixteen (19%) patients were managed at home and 68 (81%) patients were referred to a HCF. Among those referred to a HCF, three (4.4%) patients had moderate effects with ingested dose ≥6.9 mg/kg. However, 27 (39.7%) patients of those referred to a HCF had an ingested dose <6 mg/kg and none of them manifested symptoms beyond minor effects. All referred patients had uneventful recovery and no sequela.

CONCLUSIONS

Children should be referred for further evaluation in acute unintentional trazodone ingestions with doses ≥6 mg/kg.

Screening for detection of new antidepressants, neuroleptics, hypnotics, and their metabolites in urine by GC-MS developed using rat liver microsomes

A gas chromatography-mass spectrometry (GC-MS) procedure for the detection of new antidepressants, neuroleptics, hypnotics, and their metabolites in urine is presented. The metabolites were first identified in rat liver microsome preparations by GC-MS after isolation and derivatization. Using these GC-MS data, a GC-MS screening was developed for urine as part of the authors' modified systematic toxicologic analysis procedure. After acid hydrolysis of a 2.5-mL aliquot of urine, a further aliquot was added. The mixture was then liquid-liquid extracted at pH 8-9, acetylated, and GC separated. Using mass chromatography with the ions m/z 58, 100, 120, 182, 195, 235, 261, 276, 284. and 293, the presence of new antidepressants, neuroleptics, hypnotics, and their metabolites could be indicated. Positive peaks could be identified by library search using the reference mass spectra recorded during the microsome studies. The intake of therapeutic doses of the following drugs could be monitored in urine: dosulepin, mirtazapine, moclobemide, nefazodone, trazodone, venlafaxine, and zolpidem. Olanzapine and zotepine were detectable in human urine only under steady-state conditions, and low-dose zopiclone was detectable only in overdose. The detection limit was less than 100 ng/mL (signal-to-noise ratio = 3) for the parent drugs.

Antidepressants, old and new. A review of their adverse effects and toxicity in overdose

The newer antidepressants are as efficacious as the older agents in the treatment of depression. They have a side effect profile that is different from the older drugs and are generally better tolerated. Drug-drug interactions do exist with some of these agents and can usually be predicted from knowledge of their metabolism. When taken in overdose as the sole agents they are rarely fatal; seizures, nausea, vomiting, decreased level of consciousness, and tachycardia are common. In combination with other drugs, toxicity can be more severe. The serotonin syndrome can occur with many of these drugs, and the emergency physician must be vigilant in the evaluation of the overdose patient. CAs and older MAOIs are still in use and remain dangerous when taken in overdose. Patients asymptomatic after a period of observation in the ED usually can be discharged after psychiatric evaluation, when it is required.

Drug Treatment of Depression

The major advantage of the new generation of antidepressants lies in their enhanced ability to avoid unwanted side effects, such as anticholinergic or cardiovascular toxicities, and in many cases, to reduce fatalities after overdose. Second-generation antidepressants are as effective as the first generation agents, but are more selective, enabling precise targeting of symptoms. Caution in recommending the newer antidepressants must be applied, however, because these agents possess differing side effects, and unforeseen toxicities may not appear until after several years of use. Conventional tricyclics should not be overlooked in managing the depressed patient. This article discusses the symptoms of major depression, followed by the latest information on second-generation antidepressants. It concludes by providing the pharmacist with guidelines for when to select a newer over an older agent.

Clinical features, pathogenesis and management of drug-induced seizures

Many classes of pharmacological agents have been implicated in cases of drug-induced seizures. The list includes antidepressant drugs, lithium salts, neuroleptics, antihistamines (H1-receptor antagonists), anticonvulsants, central nervous system stimulants, general and local anaesthetics, antiarrhythmic drugs, narcotic and non-narcotic analgesics, non-steroidal anti-inflammatory drugs, antimicrobial agents, antifungal agents, antimalarial drugs, antineoplastic drugs, immunosuppressive drugs, radiological contrast agents and vaccines. For each of these classes of drugs, this article offers a revision of the literature and emphasises in particular the frequency of the adverse reaction, its clinical presentation, its presumed epileptogenic mechanism and the therapeutic strategy for the management of drug-induced seizures. An attempt is also made to distinguish seizures induced by standard dosages from those provoked by accidental or self-induced intoxication. For some classes of drugs such as antidepressants, neuroleptics, central nervous system stimulants (e.g. theophylline, cocaine, amphetamines) and beta-lactam antibiotics, seizures are a well recognised adverse reaction, and a large body of literature has been published discussing exhaustively the major aspects of the issue; sufficient data are available also for the other classes of pharmacological agents mentioned above. In contrast, several other drugs [e.g. allopurinol, digoxin, cimetidine, protirelin (thyrotrophin releasing hormone), bromocriptine, domperidone, insulin, fenformin, penicillamine, probenecid, verapamil, methyldopa] have not been studied thoroughly under this aspect, and the only source of information is the occasional case report. This review does not address the issue of seizures induced by drug withdrawal.

Effects of trazodone on the sleep of depressed subjects--a polygraphic study

The effects of 400-600 mg trazodone on the sleep patterns of ten depressed in-patients treated for 5 weeks were studied during the initial (days 1-3) and terminal (days 26-28) treatment periods. The sleep parameters were compared to those obtained from three sleep recordings performed just prior to the initiation of the treatment and after 2 adaptation nights at the end of a 2-week drug-free period. At the same time, the clinical evolution of patients was evaluated weekly using MADRS and Hamilton-Anxiety scales for anxiety-depression symptomatology and Spiegel and Norris sleep scales. Weekly blood samples were collected to measure plasma levels of trazodone and, at the end of the study, the elimination half-life at steady state was calculated by repeated measurements of plasma levels. Clinical improvement, as assessed by a reduction of more than 60% in MADRS scale scores, was accompanied by evidence of the definitely beneficial effects of trazodone on the disturbed sleep of these depressed patients. From the beginning of treatment, there was a hypnotic-like effect (increase in total duration of sleep and stage II, decrease in sleep latency and intrasleep awakenings). In addition, records at the end of the study showed an increase in delta sleep and an increase in REM latency, an effect classically associated with an antidepressant action. These particularly valuable effects of trazodone on sleep would suggest that this drug should especially be given in cases of depression with major insomnia.

Clinical features and management of self-poisoning with newer antidepressants

Over the last decade a number of antidepressants have been introduced which differ either chemically, pharmacologically or toxicologically from established tricyclic and monoamine oxidase drugs. Of those presently available, maprotiline is similar in toxicity to tricyclic antidepressants perhaps causing convulsions more frequently. Lofepramine is metabolised to desmethylimipramine, but the limited clinical experience so far suggests that toxicity is less severe than with other tricyclic antidepressants. Amoxapine causes coma, convulsions and less frequently renal failure, but electrocardiographic abnormalities are uncommon. Mianserin and trazodone both cause drowsiness and more infrequently deeper grades of coma. Alprazolam produces the typical benzodiazepine overdose symptoms of drowsiness and floppiness. There is as yet insufficient clinical data to comment on the specific toxicity of fluoxetine and fluvoxamine. There are many more new antidepressants in various stages of development and it is likely that several of these will be marketed. Since their individual toxicities differ it is essential that monitoring of their overdose effects should be undertaken.

Management of poisoning associated with "newer" antidepressant agents

Overdose of tricyclic antidepressants remains one of the most difficult poisonings to manage optimally in the emergency department, primarily due to the extremely rapid onset of life-threatening symptomatology. The continued high incidence of such overdoses has ensured that morbidity and mortality rates also remain unacceptably high. The development of the "second-generation antidepressants," with apparently different pharmacology and toxicity after overdose, has been an attempt to address this serious medical problem. This report reviews the published literature on the overdose toxicology of the newer cyclic antidepressants currently available in the United States--amoxapine, maprotiline, and trazodone. Nomifensine, released by the FDA in 1984, recently has been voluntarily withdrawn from the world market. Bupropion, released in 1985, also has been voluntarily withdrawn by the manufacturer three months after its release.

Second generation antidepressants: a comparative review

The authors review four "second generation" antidepressants (maprotiline, amoxapine, trazodone, and nomifensine) in terms of action on biogenic amines and receptors, antidepressive efficacy, and adverse effects. Doxepin is used as a comparative agent and is similar to the prototypical tricyclic agents in all the above categories. Maprotiline is a selective noradrenergic agent, but shares a similar adverse effect profile with doxepin and may be associated with a high frequency of seizures in overdose. Amoxapine is a mixed action antidepressant with significant neuroleptic activity in vivo. Its adverse effect profile is highlighted by symptoms related to its neuroleptic activity, and seizures and acute renal failure in overdose. Trazodone is a selective serotonergic agent with low anticholinergic activity, and minimal morbidity/mortality in overdose. Reports of priapism, leading to impotence in some men, however, is of concern. Nomifensine is a potent noradrenergic and dopaminergic agent with low anticholinergic activity, and minimum cardiotoxicity and low morbidity/mortality in overdose. Its most important adverse effects include overstimulation and infrequent, usually reversible, immunologic hypersensitivity reactions. Trazodone and nomifensine have favorable profiles for use in the elderly. Trazodone may be more favorable in the anxious/agitated patient due to its sedative effects, whereas nomifensine may be more beneficial in the retarded, apathetic patient.