'Atypical' antidepressants in overdose: clinical considerations with respect to safety

Therapeutic Implications of microRNAs in Depressive Disorders: A Review

MicroRNAs are hidden players in complex psychophysical phenomena such as depression and anxiety related disorders though the activation and deactivation of multiple proteins in signaling cascades. Depression is classified as a mood disorder and described as feelings of sadness, loss, or anger that interfere with a person’s everyday activities. In this review, we have focused on exploration of the significant role of miRNAs in depression by affecting associated target proteins (cellular and synaptic) and their signaling pathways which can be controlled by the attachment of miRNAs at transcriptional and translational levels. Moreover, miRNAs have potential role as biomarkers and may help to cure depression through involvement and interactions with multiple pharmacological and physiological therapies. Taken together, miRNAs might be considered as promising novel therapy targets themselves and may interfere with currently available antidepressant treatments.

Intralipid administration in case of a severe venlafaxine overdose in a patient with previous gastric bypass surgery

This case describes a patient with a history of bariatric surgery who was admitted to our hospital with a severe venlafaxine intoxication. Due to the altered anatomy of the gastrointestinal tract, the use of oral activated charcoal and large volumes of laxatives to prevent further uptake of venlafaxine was hampered. This resulted in massive absorption and a severe serotonergic syndrome. The patient was successfully treated with intravenous lipid emulsion.

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We describe a patient with bariatric surgery and a severe venlafaxine intoxication.

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The altered GI-tract hampered the use of activated charcoal and laxatives.

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This resulted in a serotonergic syndrome, successfully treated with Intralipid.

Pharmacological Augmentation in Unipolar Depression: A Guide to the Guidelines

BACKGROUND

Pharmacological augmentation is a recommended strategy for patients with treatment-resistant depression. A range of guidelines provide advice on treatment selection, prescription, monitoring and discontinuation, but variation in the content and quality of guidelines may limit the provision of objective, evidence-based care. This is of importance given the side effect burden and poorer long-term outcomes associated with polypharmacy and treatment-resistant depression. This review provides a definitive overview of pharmacological augmentation recommendations by assessing the quality of guidelines for depression and comparing the recommendations made.

METHODS

A systematic literature search identified current treatment guidelines for depression published in English. Guidelines were quality assessed using the Appraisal of Guidelines for Research and Evaluation II tool. Data relating to the prescription of pharmacological augmenters were extracted from those developed with sufficient rigor, and the included recommendations compared.

RESULTS

Total of 1696 records were identified, 19 guidelines were assessed for quality, and 10 were included. Guidelines differed in their quality, the stage at which augmentation was recommended, the agents included, and the evidence base cited. Lithium and atypical antipsychotics were recommended by all 10, though the specific advice was not consistent. Of the 15 augmenters identified, no others were universally recommended.

CONCLUSIONS

This review provides a comprehensive overview of current pharmacological augmentation recommendations for major depression and will support clinicians in selecting appropriate treatment guidance. Although some variation can be accounted for by date of guideline publication, and limited evidence from clinical trials, there is a clear need for greater consistency across guidelines to ensure patients receive consistent evidence-based care.

Toxin-Induced Seizures

New toxins are emerging all the time. In this article, the authors review common toxins that cause seizure, their mechanisms, associated toxidromes, and treatments. Stimulants, cholinergic agents, gamma-aminobutyric acid antagonists, glutamate agonists, histamine and adenosine antagonists, and withdrawal states are highlighted. Understanding current mechanisms for common toxin-induced seizures can promote understanding for future toxins and predicting if seizure may occur as a result of toxicity.

Monitoring for antidepressant-associated adverse events in the treatment of patients with major depressive disorder: An international consensus statement

OBJECTIVES

These recommendations were designed to ensure safety for patients with major depressive disorder (MDD) and to aid monitoring and management of adverse effects during treatment with approved antidepressant medications. The recommendations aim to inform prescribers about both the risks associated with these treatments and approaches for mitigating such risks.

METHODS

Expert contributors were sought internationally by contacting representatives of key stakeholder professional societies in the treatment of MDD (ASBDD, CANMAT, WFSBP and ISAD). The manuscript was drafted through iterative editing to ensure consensus.

RESULTS

Adequate risk assessment prior to commencing pharmacotherapy, and safety monitoring during pharmacotherapy are essential to mitigate adverse events, optimise the benefits of treatment, and detect and assess adverse events when they occur. Risk factors for pharmacotherapy vary with individual patient characteristics and medication regimens. Risk factors for each patient need to be carefully assessed prior to initiating pharmacotherapy, and appropriate individualised treatment choices need to be selected. Some antidepressants are associated with specific safety concerns which were addressed.

CONCLUSIONS

Risks of adverse outcomes with antidepressant treatment can be managed through appropriate assessment and monitoring to improve the risk benefit ratio and improve clinical outcomes.

Toxicology in the ICU: Part 2: specific toxins

This is the second of a three-part series that reviews the generalized care of poisoned patients in the ICU. This article focuses on specific agents grouped into categories, including analgesics, anticoagulants, cardiovascular drugs, dissociative agents, carbon monoxide, cyanide, methemoglobinemia, cholinergic agents, psychoactive medications, sedative-hypnotics, amphetamine-like drugs, toxic alcohols, and withdrawal states. The first article discussed the general approach to the toxicology patient, including laboratory testing; the third article will cover natural toxins.

Self-poisoning in older adults: patterns of drug ingestion and clinical outcomes

BACKGROUND AND AIMS

self-poisoning accounts for a substantial proportion of acute medical hospital presentations, but has been poorly characterised in older adults. This study sought to determine the agents ingested by older adults presenting to hospital after drug overdose, and to compare clinical outcomes to younger patients.

METHODS

a retrospective observational study of patients admitted via the emergency department due to drug overdose between 2004 and 2007.

RESULTS

during the study period, there were 8,059 admissions, including 4,632 women (57.5%). This included a subgroup of 361 patients (4.5%) who were >60 years of age. This subgroup was more likely to require hospital stay >1 night, odds ratio (95% confidence interval) = 4.3 (3.6-5.5, P < 0.0001), transfer to a critical care area = 3.8 (1.1-13.0, P = 0.0340) and had higher mortality = 4.8 (1.1-22.1, P = 0.0463). A higher proportion of older patients required transfer to a psychiatric unit (P < 0.0001) or to a general medical ward (P < 0.0001) than younger adults.

CONCLUSIONS

older adults that presented to hospital after drug overdose had ingested different drugs than younger patients, possibly due to different prescribing patterns, and had a poorer outcome. The use of drugs associated with significant toxicity should be avoided in older patients at risk of self-harm.

Drug-induced serotonin syndrome: a review

Serotonin syndrome, or serotonin toxicity (ST), is a clinical condition that occurs as a result of an iatrogenic drug-induced increase in intrasynaptic serotonin levels primarily resulting in activation of serotonin(2A) receptors in the central nervous system. The severity of symptoms spans a spectrum of toxicity that correlates with the intrasynaptic serotonin concentration. Although numerous drugs have been implicated in ST, life-threatening cases generally occur only when monoamine oxidase inhibitors are combined with either selective or nonselective serotonin re-uptake inhibitors. The triad of clinical features consists of neuromuscular hyperactivity, autonomic hyperactivity and altered mental status, which may present abruptly and progress rapidly. The awareness of ST is crucial not only in avoiding the unintentional lethal combination of therapeutic drugs but also in recognizing the clinical picture when it occurs so that treatment can be promptly initiated. In this review, the pathophysiology, clinical features, implicated drugs, diagnosis and treatment of ST are discussed.

Attention-deficit/hyperactivity disorder in pediatric patients with epilepsy: review of pharmacological treatment

Attention-deficit/hyperactivity disorder (ADHD) in children with epilepsy is a common source of impairment. Based on review of Medline indexed articles, meeting abstracts, and data requested from drug manufacturers, a summary of evidence that might guide treatment and research is presented. Methylphenidate (MPH) has shown high response rates and no increase in seizures in small trials. However, low baseline seizure rates, small numbers of subjects, and short observation periods limit the power of these studies to detect increases in seizure risk. Although longer-term effects of MPH and its effects in children with frequent seizures need to be studied, the evidence available at this time best supports use of MPH for the treatment of ADHD not amenable to changes in antiepileptic drugs or improvements in seizure control. This treatment should be part of a biopsychosocial approach. Other agents show promise. Preclinical, retrospective and open-label studies on amphetamines and atomoxetine support undertaking randomized controlled studies of these agents in patients with ADHD plus epilepsy. In contrast, additional data on guanfacine and modafinil should be gathered before undertaking randomized controlled studies with these agents.

Mirtazapine does not affect pentylenetetrazole- and maximal electroconvulsive shock-induced seizures in mice

Mirtazapine is an antidepressant exhibiting both noradrenergic and serotonergic activity. We have investigated the effects of mirtazapine on pentylenetetrazole (PTZ)- and maximal electroconvulsive shock (MES)-induced seizures in mice. Mirtazapine (1.25-20mg/kg) or saline was administered, and locomotor activity was evaluated for 30 min. One hour after administration of mirtazapine (1.25-5mg/kg) or saline, PTZ (80 mg/kg) was injected intraperitoneally into the mice. Immediately afterward, times of onset of the first myoclonic jerk (FMJ), generalized clonic seizures (GCS), and tonic extension (TE) were recorded. In the MES groups, we used the MES protocol to induce convulsions characterized by tonic hindlimb extension. Similarly, 1h after mirtazapine or saline administration, an electroshock was evoked by ear-clip electrodes to induce convulsion. Mirtazapine, at 10 and 20 mg/kg, depressed locomotor activity. Doses of 1.25-5mg/kg had no significant effect on the time of onset of FMJ, GCS, or TE induced by PTZ; on the duration of GCS and TE; or on the latency to reinstatement of the righting reflex after MES administration. Our results suggest that mirtazapine neither aggravates nor alleviates PTZ- or MES-induced seizures in mice.

Atypical antipsychotics and newer antidepressants

Atypical antipsychotics and newer antidepressants are commonly prescribed medications responsible for tens of thousands of adverse drug exposures each year. The emergency medicine physician should have a basic understanding of the pharmacology and toxicity of these agents. This knowledge is crucial to providing proper care and timely management of patients presenting with adverse drug effects from exposure to atypical antipsychotics and newer antidepressants.

Bipolar depression: diagnostic and treatment considerations

Bipolar affective disorder is a recurrent, disabling, and potentially lethal illness that typically begins early in life. Although the disorder is defined by the manic and hypomanic episodes, for most people the depression episodes are the more virulent aspect of the illness. Specifically, the depressive episodes are more numerous, last longer, and are more difficult to treat than the manias, and depression is the principal cause of the illness's increased mortality due to suicide. For people with early-onset depression, predictors of subsequent bipolarity include a family history, psychotic features, and reverse neurovegetative features. Initial episodes of depression are commonly misdiagnosed, which often delays initiation of appropriate therapy and increases the likelihood of treatment with antidepressants alone. Unfortunately, the correct diagnosis is often not made until there has been a treatment-emergent affective switch. There are no treatments specifically approved for bipolar disorder in youth and, among antidepressants, only fluoxetine has received approved. When bipolarity is suspected, treatment with mood stabilizers, both conventional (i.e., lithium, valproate, and carbamazapine) and more recently classified (lamotrigine) and atypical antipsychotics should be prioritized. When antidepressants are indicated in combination with mood stabilizers, first choice options include bupropion and the selective serotonin reuptake inhibitors. Studies of adults indicate that several forms of focused psychotherapy may improve longer term outcomes.

Risk of serotonin syndrome with concomitant administration of linezolid and serotonin agonists

Linezolid, an antimicrobial used to treat resistant gram-positive bacteria, can inhibit monoamine oxidase, an enzyme that metabolizes serotonin and other biogenic amines. Inhibition of this enzyme can predispose patients who are concomitantly taking serotonin agonists to serotonin syndrome. Because of the potential of linezolid to inhibit monoamine oxidase, premarketing studies were conducted with drugs such as selective serotonin reuptake inhibitors. No cases of serotonin syndrome were recorded. After linezolid was released to the United States market, several case reports of serotonin syndrome emerged. A literature search revealed 13 cases of serotonin syndrome occurring with the concomitant use of linezolid and drugs possessing serotonergic properties. To direct clinical management of this potential drug interaction, we reviewed reports of serotonin syndrome to determine relevant drug interactions with linezolid and serotonergic drugs and to characterize similarities and differences in the reported cases. Clinicians should obtain complete drug histories to identify patients at risk, strictly monitor drug therapy including concomitant drugs, and receive education about this potential drug interaction and the symptoms of serotonin syndrome.

A review of serotonin toxicity data: implications for the mechanisms of antidepressant drug action

Data now exist from which an accurate definition for serotonin toxicity (ST), or serotonin syndrome, has been developed; this has also lead to precise, validated decision rules for diagnosis. The spectrum concept formulates ST as a continuum of serotonergic effects, mediated by the degree of elevation of intrasynaptic serotonin. This progresses from side effects through to toxicity; the concept emphasizes that it is a form of poisoning, not an idiosyncratic reaction. Observations of the degree of ST precipitated by overdoses of different classes of drugs can elucidate mechanisms and potency of drug actions. There is now sufficient pharmacological data on some drugs to enable a prediction of which ones will be at risk of precipitating ST, either by themselves or in combinations with other drugs. This indicates that some antidepressant drugs, presently thought to have serotonergic effects in animals, do not exhibit such effects in humans. Mirtazapine is unable to precipitate serotonin toxicity in overdose or to cause serotonin toxicity when mixed with monoamine oxidase inhibitors, and moclobemide is unable to precipitate serotonin toxicity in overdose. Tricyclic antidepressants (other than clomipramine and imipramine) do not precipitate serotonin toxicity and might not elevate serotonin or have a dual action, as has been assumed.

Antidepressants and seizures: emphasis on newer agents and clinical implications

Seizures are a known, relatively rare, consequence of antidepressant treatment. Risk estimates vary depending on the study, source of data and patient population, predisposed vs. nonpredisposed. For newer antidepressants (e.g. selective serotonin reuptake inhibitors, bupropion, mirtazepine, etc.), the risk is generally considered to be low (0.0%-0.4%) and not very different from the incidence of first seizure in the general population (0.07%-0.09%). Risk with tricyclic antidepressants at effective therapeutic doses is relatively high (0.4% to 1-2%). Seizure following overdose is a significant and relatively frequent event for some antidepressants. Patients being considered for antidepressant treatment should be screened for predisposition to seizures. Predisposed patients should receive antidepressants cautiously. The seizure potential of antidepressants in patients without a predisposition is low, especially for newer antidepressants. Seizure risk, along with other drug-related considerations, e.g. weight gain, sexual dysfunction and sedation, should be considered when prescribing an antidepressant.

Intraventricular conduction delay after bupropion overdose

Bupropion overdose mainly is characterized by tachycardia, agitation, and seizures. The few reports of QRS complex widening after bupropion overdose that have been published in peer-reviewed literature are notable for failure to have confirmed elevated plasma bupropion concentrations or failure to have excluded other causes of QRS widening. We describe two patients in whom bupropion overdose was confirmed with elevated plasma bupropion concentrations and in whom other cardiotoxic ingestions were excluded with comprehensive analytical toxicology testing. Our findings are in keeping with ex vivo studies in which bupropion antagonizes cardiac voltage-gated sodium channels. Bupropion overdose should be considered in the differential diagnosis of unexpected QRS widening.