A case of serotonin syndrome induced by concomitant treatment with low-dose trazodone and amitriptyline and lithium

R, Patel PH, Bazan DZ, Mora A, Samuel N, Mingle AC, Leon LR, Varon J, Surani S. Drug-Induced Hyperthermia Review

Humans maintain core body temperature via a complicated system of physiologic mechanisms that counteract heat/cold fluctuations from metabolism, exertion, and the environment. Overextension of these mechanisms or disruption of body temperature homeostasis leads to bodily dysfunction, culminating in a syndrome analogous to exertional heat stroke (EHS). The inability of this thermoregulatory process to maintain the body temperature is caused by either thermal stress or certain drugs. EHS is a syndrome characterized by hyperthermia and the activation of systemic inflammation. Several drug-induced hyperthermic syndromes may resemble EHS and share common mechanisms. The purpose of this article is to review the current literature and compare exertional heat stroke (EHS) to three of the most widely studied drug-induced hyperthermic syndromes: malignant hyperthermia (MH), neuroleptic malignant syndrome (NMS), and serotonin syndrome (SS). Drugs and drug classes that have been implicated in these conditions include amphetamines, diuretics, cocaine, antipsychotics, metoclopramide, selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), and many more. Observations suggest that severe or fulminant cases of drug-induced hyperthermia may evolve into an inflammatory syndrome best described as heat stroke. Their underlying mechanisms, symptoms, and treatment approaches will be reviewed to assist in accurate diagnosis, which will impact the management of potentially life-threatening complications.

The Link Between Amitriptyline and Movement Disorders: Clinical Profile and Outcome

INTRODUCTION

Amitriptyline (AMT) is a tricyclic antidepressant. In this review, we evaluate the clinical and epidemiological profile, pathological mechanisms and management of AMT-associated movement disorders.

MATERIALS AND METHODS

A search for relevant reports in 6 databases was performed. Studies that reported patients developed only ataxia or tremor after AMT use were excluded.

RESULTS

A total of 48 reports on 200 cases were found. AMT-associated movement disorders included myoclonus (n = 26), dyskinesia (n = 11), dystonia (n = 8), stutter (n = 5), akathisia (n = 3) and restless legs syndrome (n = 1). For less well-defined cases, 99 patients had dyskinesia, 19 had psychomotor disturbances, 3 had myoclonus, 11 had dystonia, 12 had Parkinsonism and 1 each had akathisia and extrapyramidal symptoms. Mean and standard deviation (SD) and median ages were 45.40 years (SD 16.78) and 40 years (range 3.7-82 years), respectively. Over half were women (58.13%) and the most common indication was depression. Mean and median AMT doses were 126 mg (SD 128.76) and 75 mg (range 15-800 mg), respectively. In 68% of patients, onset of movement disorders was <1 month; time from AMT withdrawal to complete recovery was <1 month in 70% of cases. A weak negative linear correlation (r = -0.0904) was found between onset of movement disorders and AMT dose. AMT withdrawal was the most common treatment.

CONCLUSION

Amitriptyline is associated with various movement disorders, particularly myoclonus, dystonia and dyskinesias. Stutters and restless legs syndrome are some of the less common associations.

Serotonin syndrome

Aims and method

To define serotonin syndrome and its symptoms and to discover which drugs or drug combinations are likely to cause it. A review of literature (including case reports) relating to serotonin syndrome collated from searches of MedLine and Micromedex covering the period January 1991 to July 1998.

Results

Most of the data found were either individual case reports or reviews of case reports. Reports of serotonin syndrome seem to be growing, certainly since the introduction of selective serotonin reuptake inhibitors. Particular combinations seem most likely to induce serotonin syndrome. Awareness of this syndrome as a distinct clinical entity seems to be growing.

Clinical implications

Serotonin syndrome is more likely to occur with drug combinations, especially those involving monoamine oxidase inhibitors. It can also occur when swapping antidepressant therapy, especially If changing from a long acting antidepressant such as fluoxetine. Caution is needed when changing antidepressants and particularly when they are used in combination.

Serotonin syndrome in patients with headache disorders

Serotonin syndrome (SS) is an iatrogenic, drug-induced syndrome caused by serotoninergic agent. Various serotonergic drugs are used in different headache disorders. Therefore, a possibility of developing SS exists in patients with headache. Herein, we are reporting two patients with headache disorders who developed SS.Case 1: a 49-year-old man had a 6-year history of episodic cluster headache (CH). However, he had never been diagnosed with CH before reporting to us. He had been receiving amitriptyline, tramadol/acetaminophen combination and flunarizine. Lithium was started for CH. He developed features consistent with SS. The patient responded to cyprohepatdine.Case 2: a 36-year-old chronic migraineur was on amitriptyline. Addition of sodium valproate led to the development of new features that fulfilled the criteria of SS. The patient responded to cyprohepatdine.As SS may be fatal, there is a need to increase awareness about SS in physicians treating patients with headache.

A review of the evidence supporting the use of lithium augmentation therapy for the reduction of suicidal behavior in patients with unipolar depression: Revisiting an overlooked benefit of an older medication

Major depressive disorder is a serious, recurrent condition with significant impact on a person's quality of life and functioning, which carries a significant risk of premature death due to suicide. There is evidence that supports the effectiveness of lithium as an augmentation strategy for treatment-resistant depression, as well as for reducing suicidality in this population. This review introduces several theories regarding the proposed mechanism behind lithium's anti-suicidal effects and summarizes a selection of the pertinent literature supporting lithium's beneficial effects on suicidality.

Linezolid-induced near-fatal serotonin syndrome during escitalopram therapy: case report and review of literature

Linezolid is a synthetic antimicrobial agent of the oxazolidinone class with weak, nonspecific inhibitor of monoamine oxidase enzymes. Concomitant therapy with an adrenergic or serotonergic agent or consuming tyramine (>100 mg/day) may induce serotonin syndrome (SS). We present a case report of near-fatal adverse interaction between linezolid and escitalopram inducing SS in a 65-year-old woman with sepsis, under empirical antibiotic treatment. This report also summarizes the current relevant literature as identified via PubMed, EMBASE, and PsycINFO, supplemented with a manual search of cross references.

Linezolid is associated with serotonin syndrome in a patient receiving amitriptyline, and fentanyl: a case report and review of the literature

We report a unique case of an adverse interaction between the oxazolidinone antibiotic linezolid, the tricyclic antidepressant amitriptyline and the opioid analgesic fentanyl in a 68-year-old woman with advanced ischemic peripheral arterial disease and sepsis, under empirical antibiotic treatment. We also summarize the current relevant literature as identified via PubMed, EMBASE, and PsycINFO as well as reference sections of selected articles.

Drug-induced movement disorders in children and adolescents

The use of psychotropic medication among children and adolescents is increasing with a concomitant increase in the incidence of drug-related movement disorders. This class of adverse reactions to medications can be divided into those that are acute in onset, others that are continuous as long as the offending drug is administered, and a final category consisting of symptoms that are persistent, even after the causative agent has been discontinued. Within these three categories, this review discusses the epidemiology, risk factors, clinical features and treatment of acute dystonic reactions, drug-induced parkinsonism, neuroleptic malignant syndrome, serotonin syndrome, acute akathisia, and the tardive syndromes. In addition, drugs that commonly cause tremor, chorea, or myoclonus are included.

Drug-induced myoclonus: frequency, mechanisms and management

Myoclonus is a sudden, abrupt, brief, 'shock-like' involuntary movement caused by muscular contractions ('positive myoclonus') or a sudden brief lapse of muscle contraction in active postural muscles ('negative myoclonus' or 'asterixis'). Various disorders can cause myoclonus including neurodegenerative and systemic metabolic disorders and CNS infections. In addition, myoclonus has been described as an adverse effect of some drugs. Level II evidence is available to indicate that levodopa, cyclic antidepressants and bismuth salts can cause myoclonus, while there is less robust evidence to associate numerous other drugs with the induction of myoclonus. The pharmacological mechanisms responsible for this adverse effect are not well established, although increased serotonergic transmission may be involved in the induction of myoclonus by several drugs. Drug-induced myoclonus usually resolves after withdrawal of the offending drug, but in some cases specific treatments are needed.

Drug-induced movement disorders in children

The increased use of stimulants, antipsychotic agents, and antidepressant drugs in children by primary care physicians, psychiatrists, and neurologists has inevitably led to increased numbers of pediatric patients manifesting the side effects of these agents, many of which are movement disorders. Unlike the isolated abnormal involuntary movements associated with drugs prescribed for epilepsy or asthma, movement syndromes (eg, acute dystonic reaction, neuroleptic malignant syndrome, serotonin syndrome, tardive dyskinesia) associated with psychotropic drugs are complex, difficult to recognize, and potentially seriously disabling. Accurate clinical identification of these drug-induced syndromes is critical to engaging the proper therapeutic intervention for them.

Interaction of lithium with 5-HT(1B) receptors in depressed unipolar patients treated with clomipramine and lithium versus clomipramine and placebo: preliminary results

Lithium is commonly used in combination with antidepressant drugs as a treatment for refractory depression; less often, it is used in non-resistant depression. The aim of this study was to examine the interaction of lithium with 5-HT(1B) receptors in 10 non-resistant unipolar depressed patients treated with clomipramine+lithium (C+L) vs. clomipramine+placebo (C+P). A mediation of the serotonergic system has been proposed in the literature to explain the clinical effect of lithium. Indeed, in a previous study of healthy human blood platelets, we demonstrated the interaction of lithium with adenylate cyclase activity coupled to 5-HT(1B) receptors. The functional activity of these receptors was measured by studying the inhibitory effect of L694,247, a 5-HT(1B) receptor agonist, on the adenylate cyclase activity determined by the production of cAMP. Using the same technique in the present study, we found that lithium significantly reduced the inhibition of adenylate cyclase activity induced by 5-HT(1B) receptor activation. This result confirms the specific interaction of lithium with 5-HT(1B) receptors. Moreover, a correlation between the percentage of 5-HT(1B) receptor-dependent adenylate cyclase inhibition and the clinical benefit of lithium was established, suggesting 5-HT(1B) receptors may be a target for the therapeutic effect of lithium.

Changes in quantitatively assessed tremor during treatment of major depression with lithium augmented by paroxetine or amitriptyline

Tremor is a relatively frequent side effect of lithium and of antidepressants with serotonergic properties. It can be expected that combinations of lithium (which is itself serotonergic) with such antidepressants will enhance not only efficacy, but also the incidence of side effects, including tremor. To quantitatively monitor the effect of antidepressant augmentation of ongoing lithium therapy on tremor, lithium-maintained patients with a breakthrough episode of major depression were randomly assigned under double-blind conditions to receive paroxetine 20 mg/day (N = 14) or amitriptyline 75 mg/day (N = 17). The initial dosages could be increased after 2 weeks to 40 mg/day and 150 mg/day, respectively, and the patients were treated for 6 weeks. Tremor activity was assessed weekly, quantitatively by accelerometry and qualitatively with the Dosage Record and Treatment Emergent Symptom Scale. Statistical analysis detected no significant difference between the treatment groups with respect to changes in mean tremor activity relative to baseline. However, analysis of the pooled data showed that tremor increased significantly during the course of combined lithium and antidepressant therapy, with the greatest increments occurring independent of dosage approximately 3 weeks after initiation of combination treatment. Although the mean tremor activity subsided toward the end of treatment, tremor activity on the whole was still significantly greater after 6 weeks of combined lithium and antidepressant treatment than at the start of combination therapy. Increased tremor was not associated with decreased medication compliance, and no patient discontinued treatment because of increased tremor. Tremor frequency was not affected by the study treatments.

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.

Serotonin syndrome: history and risk

This review focuses on the history of investigations into the behavioural reaction resulting from excess stimulation of post-synaptic 5-hydroxytryptamine receptors and the relative risk of this occurring with different combinations of drugs. Other aspects, particularly treatment with 5-hydroxytryptamine receptor antagonists, are reviewed in a recent separate paper [44]. The first human case was in 1955 and animal work had defined the characteristic features by 1958, and established they were lessened by chlorpromazine. Substantial evidence of a 'dose-effect' relationship existed by 1984. The relative risk with different drug combinations is assessed from available evidence and argued to be strongly associated with the degree of elevation of 5-hydroxytryptamine, which is greatest following combinations of irreversible inhibitors of monoamine oxidase A and B with potent serotonin reuptake inhibitors. The various serotonergic drugs that may be implicated in serotonin syndrome are tabulated and discussed in relation to the relative risk. It is suggested that the proposed 'diagnostic criteria' for serotonin syndrome are inappropriate since there is a continuous spectrum from side effects to toxicity. The term 'serotonin syndrome' may encourage the presumption that it is an idiosyncratic response, as neuroleptic malignant syndrome is usually considered to be. The terms 'toxic serotomimetic reaction' or 'toxic serotonin syndrome' may be preferable alternatives. The differences between serotonin syndrome and neuroleptic malignant syndrome are highlighted with examples from difficult or questionable cases in the recent literature. It is proposed that more systematic national collection of toxicity data is essential in order to quantify the relative risk of serotonin syndrome with various combinations of serotonergic drugs.

Serotonergic synergism: the risks and benefits of combining the selective serotonin reuptake inhibitors with other serotonergic drugs

It has become common clinical practice to combine the selective serotonin reuptake inhibitors with other serotonergic agents for augmentation or adjunctive purposes. The empirical basis for using these combinations remains limited, but is growing. Also growing is a literature that suggests that even the most apparently benign combinations of serotonergic drugs carry at least some risk of serious pharmacokinetic or pharmacodynamic drug interactions, such as a serotonin syndrome.