Serotonin syndrome: early management with cyproheptadine

Serotonin syndrome: A rare yet crucial diagnosis

ABSTRACT

Serotonin syndrome is a rare, life-threatening toxidrome caused by serotonergic agents. This syndrome classically presents with a combination of mental status changes, autonomic hyperactivity, and neuromuscular abnormalities. However, diagnosing the condition is difficult because of its variable symptoms at presentation. As a result, serotonin syndrome often is underreported, making it harder to understand, recognize, and treat. Patients with this condition may present to primary or urgent care or an ED, and may become acutely symptomatic during an inpatient admission. Clinicians must be able to identify at-risk patients and intervene to prevent potentially lethal complications.

Management of serotonin syndrome (toxicity)

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

A suspected case of serotonin syndrome induced by palonosetron and ramosetron administration

Serotonin syndrome occurs when serotonin (5-hydroxytryptamine, 5-HT) levels increase and is accompanied by symptoms of mental status changes, neuromuscular abnormalities, and autonomic hyperactivity. Serotonin receptor 3 antagonists, such as palonosetron or ramosetron, are commonly used for their antiemetic effects during general anesthesia. However, overdosage of these drugs carries a risk of serotonergic toxicity as they increase serum serotonin levels due to inhibition of serotonin reuptake. Serotonin syndrome caused by 5-HT3 antagonists is thought to be caused by the synergistic effects of high doses of serotonergic drugs or the combination of two or more serotonergic drugs with different mechanisms of action. The incidence of serotonin syndrome is unknown because it is a rare condition that cannot be selected for in randomized clinical trials. Therefore, physicians must focus on the clinical manifestations of the syndrome and manage patients before the condition becomes life-threatening.

Therapeutic cyproheptadine regimen in serotonin syndrome: Complications after cardiovascular surgery

Serotonin syndrome can be a life-threatening condition that occurs from the overactivity of serotonin in the central nervous system. This report describes the use of cyproheptadine for the management of serotonin syndrome in a patient taking fluoxetine and bupropion, who received methylene blue for vasoplegia syndrome. A 61-year-old female taking fluoxetine and bupropion preoperatively was given a total of three doses of methylene blue 100 mg IV within a brief time frame during and after a planned coronary artery bypass graft surgery. Postoperatively, the patient was not following commands, was agitated and confused, febrile with diaphoresis, tachycardic, had muscle rigidity, and horizontal ocular clonus. The patient's presentation was most consistent with serotonin syndrome due to a drug-drug interaction. Cyproheptadine and supportive care were used successfully to treat serotonin syndrome, and the patient was discharged home 14 days postoperatively. Based on the literature, there is no standardized method of weaning cyproheptadine when used for serotonin syndrome. The patient in our case received a total of 188 mg of cyproheptadine over the course of 10 days and did not experience any side effects. This case highlights a potential dosing regimen that can be used for other patients.

Escitalopram, bupropion, lurasidone, lamotrigine and possible vortioxetine overdose presented with serotonin syndrome and diffuse encephalopathy: A case report

BACKGROUND

Psychotropic drugs can cause neurological effects when overdosed. This study reports a case of psychotropic drugs overdose presenting with serotonin toxicity and encephalopathy.

CASE PRESENTATION

A 20-year-old female with major depression presented with agitation 3 h after an overdose on multiple medications. Her current medications were vortioxetine, lamotrigine, lurasidone, and bupropion (extended-release). Vital signs showed hyperthermia and tachycardia. Neurological examination was remarkable for mydriasis and hyperreflexia with inducible ankle clonus. The electrocardiography showed sinus tachycardia with QTc 480 ms. Twelve hours later, she became obtunded and developed subcortical myoclonus. The electroencephalogram demonstrated a diffuse encephalopathy pattern without epileptic activities. She was diagnosed with serotonin syndrome based on Hunter Serotonin Toxicity Criteria. Myoclonus and abnormal vital signs resolved within hours after cyproheptadine administration, but she remained unconscious for 3.5 days. Urine drug screening was positive for benzodiazepines and metabolites, lamotrigine, escitalopram, and hydroxybupropion. This suggested she had overdosed on escitalopram which had been previously prescribed. Unfortunately, vortioxetine and lurasidone could not be detected by our current facilities.

CONCLUSION

This case exhibited serotonin syndrome and encephalopathy from overdose of multiple psychotropic agents. Her prolonged depressed consciousness could be explained by the half-life of the drugs and possible drug interactions.

Antiepileptic drugs and serotonin syndrome- A systematic review of case series and case reports

Serotonin syndrome (SS) is a drug‑induced, potentially fatal, clinical syndrome resulting from drugs that have serotonergic properties. Several antiepileptic drugs (AEDs) are known to have serotonergic properties and it can be hypothesized that such AEDs can cause SS. This study aims to review the literature on SS in patients receiving AEDs. We performed a systematic review of Scopus and MEDLINE/PUBMED for case reports and case series of SS where patients had received at least one AED at the onset of symptoms. The cases published in the English literature between 1 January 1991 and 1 April 2021 were included. Initial search identified 1263 articles of which 63 (76 patients) were included in the final analysis. Most of the included cases (53 cases, 70%) have been published in the last 10 years. The mean age of the 76 patients was 40.6 ± 17.8 years, and 51% of cases were females. These patients had been exposed to a total of 8 different types of AEDs. Valproic acid was the most common drug (29, 38%), followed by lamotrigine (22, 29%), gabapentin (16, 21%), pregabalin (seven, 9%), topiramate (five, 7%) and carbamazepine (two, 3%). There has been one case each with phenytoin and oxcarbazepine. Seven (9%) patients received more than one AEDs. Most patients (67, 88%) also received other serotoninergic agents. Only nine (12%) patients were on AEDs alone. The most common clinical condition for using AEDs was psychiatric disorders (36 patients, 47.3%), followed by migraine (17, 22.4%), other painful conditions (15, 19.7%), epilepsy (7, 9.2%), and perioperative conditions (8, 10.5%). Death was reported in two patients. We suggest that AEDs, because of their serotonergic properties, may induce SS, especially in patients who are on another serotonergic agent.

Two Cases of Serotonin Syndrome After Bupropion Overdose Treated With Cyproheptadine

BACKGROUND

Bupropion is not known to have direct serotonin agonism or inhibit serotonin reuptake. In spite of this, it has been implicated as a causative agent of serotonin syndrome. We highlight two cases of single-agent bupropion overdose that subsequently met the diagnosis of serotonin syndrome by the Hunter criteria, despite the absence of direct serotonergic agents. CASE 1: A 14-year-old boy intentionally ingested an estimated 30 bupropion 75-mg immediate-release tablets. He presented in status epilepticus, was intubated, and was placed on midazolam and fentanyl infusions. He developed tremor, ankle clonus, and agitation. He was administered cyproheptadine for presumed serotonin syndrome with temporal improvement in his symptoms. CASE 2: A 19-year-old woman intentionally ingested an estimated 53 bupropion 150-mg extended-release tablets. She had a seizure and required sedation and intubation. During her course, she developed hyperthermia, inducible clonus, and hyperreflexia. She was treated with cyproheptadine without temporal improvement of symptoms but improved the following day. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although bupropion is not known to be directly serotonergic, it has been implicated as the single causative agent after overdose. This may be due to an indirect increase in activity of serotonergic cells. In these cases, bupropion overdose resulted in a clinical presentation consistent with serotonin syndrome, with the first having a temporal improvement after treatment with cyproheptadine. Physicians need to be aware of the potential serotonergic activity of bupropion for accurate assessment and treatment of this dangerous condition.

Serotonin Toxicity: Associated Agents and Clinical Characteristics

BACKGROUND

Serotonin toxicity is a common cause of drug-induced altered mental status. However, data on the causes of serotonin toxicity, symptomatology, complications, and rate of antidotal treatment are limited.

METHODS

This study evaluated cases of serotonin toxicity in the ToxIC registry, an international database of prospectively collected cases seen by medical toxicologists. Serotonin toxicity was diagnosed by bedside evaluation of medical toxicology specialists and explicit criteria were not used. The database was searched for "serotonin syndrome" between January 1, 2010, and December 31, 2016.

RESULTS

There were 1010 cases included. Females made up 608 (60%) cases. Ages are as follows: younger than 2 years (3, 0.3%), 2 to 6 years (8, 0.8%), 7 to 12 years (9, 0.9%), 13 to 18 years (276, 27.3%), 19 to 65 years (675, 67%), older than 66 years (33, 3.4%), unknown (6, 0.6%). Reasons for encounter: intentional (768, 76%), adverse drug event/reaction (127, 12.6%), unintentional (66, 6%), and unknown (55, 5.4%). Signs/symptoms: hyperreflexia/clonus/myoclonus (601, 59.5%), agitation (337, 33.4%), tachycardia (256, 25.3%), rigidity (140, 13.9%), seizures (139, 13.7%), and hyperthermia (29, 2.9%).

COMPLICATIONS

rhabdomyolysis (97, 9.7%), dysrhythmias (8, 0.8%), and death (1, 0.1%).

TREATMENTS

benzodiazepines 67% (677/1010), cyproheptadine 15.1% (153/1010). There were 192 different xenobiotics reported with 2046 total exposures. Antidepressants were most common (915, 44.7%) with bupropion the most frequent overall (147, 7.2%). Common non-antidepressants were dextromethorphan (95, 6.9%), lamotrigine (64, 3.1%), and tramadol (60, 2.9%).

DISCUSSION

Serotonin toxicity most often occurred in adult patients with intentional overdose. Antidepressants were the most common agents of toxicity. Interestingly, bupropion, a norepinephrine/dopamine reuptake inhibitor, was the most frequently mentioned xenobiotic. Though often cited as a potential antidote, only 15% of patients received cyproheptadine. Severe toxicity was rare. A single death was reported.

Serotonin Syndrome in the Emergency Department

With the widespread use of serotonergic agents including many antidepressants, antiemetics, illicit drugs, and even some herbal supplements, serotonin syndrome is a condition seen more frequently. It can appear abruptly and, if untreated, can progress to a life-threatening state. Prompt recognition and treatment is imperative to avoid complications. The presentation is variable and can be confused with other conditions. The authors present a case of serotonin syndrome that was recognized early and treated promptly in the emergency department.

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

Serotonin syndrome (SS) (also referred to as serotonin toxicity) is a potentially life-threatening drug-induced toxidrome associated with increased serotonergic activity in both the peripheral (PNS) and central nervous systems (CNS). It is characterised by a dose-relevant spectrum of clinical findings related to the level of free serotonin (5-hydroxytryptamine [5-HT]), or 5-HT receptor activation (predominantly the 5-HT_1A and 5-HT_2A subtypes), which include neuromuscular abnormalities, autonomic hyperactivity, and mental state changes. Severe SS is only usually precipitated by the simultaneous initiation of 2 or more serotonergic drugs, but the syndrome can also occur after the initiation of a single serotonergic drug in a susceptible individual, the addition of a second or third agent to long-standing doses of a maintenance serotonergic drug, or after an overdose. The combination of a monoamine oxidase inhibitor (MAOI), in particular MAO-A inhibitors that preferentially inhibit the metabolism of 5-HT, with serotonergic drugs is especially dangerous, and may lead to the most severe form of the syndrome, and occasionally death. This review describes our current understanding of the pathophysiology, clinical presentation and management of SS, and summarises some of the drugs and interactions that may precipitate the condition. We also discuss the newer novel psychoactive substances (NPSs), a growing public health concern due to their increased availability and use, and their potential risk to evoke the syndrome. Finally, we discuss whether the inhibition of tryptophan hydroxylase (TPH), in particular the neuronal isoform (TPH2), may provide an opportunity to pharmacologically target central 5-HT synthesis, and so develop new treatments for severe, life-threatening SS.

The Serotonin Syndrome: From Molecular Mechanisms to Clinical Practice

The serotonin syndrome is a medication-induced condition resulting from serotonergic hyperactivity, usually involving antidepressant medications. As the number of patients experiencing medically-treated major depressive disorder increases, so does the population at risk for experiencing serotonin syndrome. Excessive synaptic stimulation of 5-HT_2A receptors results in autonomic and neuromuscular aberrations with potentially life-threatening consequences. In this review, we will outline the molecular basis of the disease and describe how pharmacologic agents that are in common clinical use can interfere with normal serotonergic pathways to result in a potentially fatal outcome. Given that serotonin syndrome can imitate other clinical conditions, an understanding of the molecular context of this condition is essential for its detection and in order to prevent rapid clinical deterioration.

Serotonin Syndrome and the Anaesthetist

Serotonin syndrome results from excessive activation of serotonin (5-hydroxytryptamine; 5-HT) receptors in the nervous system, on the surface of platelets, and on the vascular endothelium. The clinical manifestations are a triad of altered conscious state, autonomic dysfunction, and neuromuscular excitability. Clinical diagnostic criteria remain poorly defined and unvalidated, and there are no available investigations to confirm the diagnosis. The syndrome is caused by the administration of one or more drugs possessing serotonergic activity. Severe forms of the syndrome usually result from overdose, but can be induced by monotherapy. The exact incidence of serotonin syndrome remains unknown, but is likely to be increasing due to increased prescription of selective serotonin reuptake inhibitor anti-depressants and tramadol, as well as recreational use of amphetamine-like substances. Serotonin syndrome may complicate the administration of drugs frequently used in anaesthetic practice, including pethidine and tramadol. Although the majority of cases improve with symptomatic and supportive care, severe cases need intensive care and frequently require mechanical ventilation. Neuromuscular excitability is likely to be the cause of rhabdomyolysis seen in severe cases and should be treated with benzodiazepines and muscle relaxants. Supportive therapies are required to treat hyperthermia and autonomic dysfunction. Cyproheptadine is the most commonly administered serotonergic antagonist, but is unavailable in parenteral form.

[The serotonin syndrome: An updated literature review]

The serotonin syndrome is a potentially deadly complication resulting from drug adverse effect, drug-drug interaction or overdose involving one or more serotonergic molecules, e.g., antidepressants, psychostimulants and sometimes an "ignored" serotonergic compound. The serotonin syndrome typically consists of a clinical triad including cognitive/behavioral, neurovegetative and neuromuscular features. However, this syndrome is characterized by major clinical heterogeneity, making the diagnosis difficult in practice. Moreover, many practitioners are quite unaware of this syndrome. Available scores and classifications can help physicians in their diagnosis approach. Knowing the responsible molecules, their potential interactions and mechanisms of action can help preventing this complication allowing therapeutic education among patients. This updated article reviews the clinical presentation, prevention, management, and pathophysiology of the serotonin syndrome, and addresses the most recent advances in pharmacogenetics regarding this syndrome.

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.

Hyperthermia syndromes in psychiatry

Presence of fever in psychiatric patients may signify a number of potentially fatal conditions. Several of these are related to treatments (e.g. neuroleptic malignant syndrome with antipsychotics, serotonin syndrome with serotonergic antidepressants, and malignant hyperpyrexia with anaesthesia used for administration of electroconvulsive therapy) or exacerbated by them (e.g. malignant catatonia with antipsychotics). New classes of drug treatment may be changing the epidemiology of these disorders. We suggest that an initial diagnosis of hyperthermia syndrome is clinically useful as there are some important commonalities in treatment. We outline a systematic approach to identify a particular subtype of hyperthermia syndrome and the indications for more specific treatments where available.

Neuroleptic malignant syndrome and serotonin syndrome

The clinical manifestation of drug-induced abnormalities in thermoregulation occurs across a variety of drug mechanisms. The aim of this chapter is to review two of the most common drug-induced hyperthermic states, serotonin syndrome and neuroleptic malignant syndrome. Clinical features, pathophysiology, and treatment strategies will be discussed, in addition to differentiating between these two syndromes and differentiating them from other hyperthermic or febrile syndromes. Our goal is to both review the current literature and to provide a practical guide to identification and treatment of these potentially life-threatening illnesses. The diagnostic and treatment recommendations made by us, and by other authors, are likely to change with a better understanding of the pathophysiology of these syndromes.

When Too Much Is Enough: Pediatric Cyproheptadine Overdose with Confirmatory Level

Cyproheptadine is an H-1 antihistamine with anticholinergic and antiserotonergic effects. Cyproheptadine’s most common use has been in the management cold-induced urticaria. It is often used in primary care for its side effect of appetite stimulation. Recently there has been increasing interest in its use in the treatment of drug-induced serotonin syndrome. Cyproheptadine overdose is uncommonly reported in the medical literature. We report the rare case of a pediatric cyproheptadine overdose with a confirmatory cyproheptadine level.

Chlordiazepoxide preventive effect on tramadol overdose induced serotonin syndrome evaluated by hunter and radomski criteria: a clinical trial

INTRODUCTION

Tramadol is an analgesic medication that is frequently abused. It has two functions; mu-opioid receptors agonism, as well as, serotonergic activities. It has shown that tramadol overdose may induce serotonin syndrome (SS). This study evaluates whether early treatment with chlordiazepoxide could prevent SS in admitted tramadol overdoses.

MATERIALS AND METHODS

In this single blind randomized control trial, 50% of admitted tramadol overdoses in Imam Reza (p) Hospital from 21 September 2011 to 21 January 2012 were recruited. Cases received chlordiazepoxide and controls received placebo. Clinical findings were recorded in a pre-designed spread sheet every 6 hours in the first 24 hours of admission. SS was determined by two independent methods; Hunter Criteria (HC) and Radomski Criteria (RC).

RESULTS

In total, five patients developed SS when HC or RC was taken into account. Among them, four cases were shared. None of the SS cases diagnosed with HC received chlordiazepoxide. However, just one SS case diagnosed with RC was from the case group. Based on HC, chlordiazepoxide decreased the Risk Ratio (CI 95%) of SS to 0.80 (0.66-0.97) (P = 0.025). This effect did not reach statistically significant levels when SS was diagnosed with RC.

CONCLUSION

This study supports the fact that pre-treatment with chlordiazepoxide could prevent tramadol overdose induced SS.

Toxicology today: what you need to know now

Clinicians are frequently confronted with toxicological emergencies and challenged with the task of correctly identifying the possible agents involved and providing appropriate treatments. In this review article, we describe the epidemiology of overdoses, provide a practical approach to the recognition and diagnosis of classic toxidromes, and discuss the initial management strategies that should be considered in all overdoses. In addition, we evaluate some of the most common agents involved in poisonings and present their respective treatments. Recognition of toxidromes with knowledge of indications for antidotes and their limitations for treating overdoses is crucial for the acute care of poisoned patients.

Triptans, serotonin agonists, and serotonin syndrome (serotonin toxicity): a review

The US Food and Drug Administration (FDA) have suggested that fatal serotonin syndrome (SS) is possible with selective serotonin reuptake inhibitors (SSRIs) and triptans: this warning affects millions of patients as these drugs are frequently given simultaneously. SS is a complex topic about which there is much misinformation. The misconception that 5-HT1A receptors can cause serious SS is still widely perpetuated, despite quality evidence that it is activation of the 5-HT2A receptor that is required for serious SS. This review considers SS involving serotonin agonists: ergotamine, lysergic acid diethylamide, bromocriptine, and buspirone, as well as triptans, and reviews the experimental foundation underpinning the latest understanding of SS. It is concluded that there is neither significant clinical evidence, nor theoretical reason, to entertain speculation about serious SS from triptans and SSRIs. The misunderstandings about SS exhibited by the FDA, and shared by the UK Medicines and Healthcare products Regulatory Agency (in relation to methylene blue), are an important issue with wide ramifications.

Serotonin syndrome risks when combining SSRI/SNRI drugs and triptans: is the FDA's alert warranted?

In 2006 the Food and Drug Administration (FDA) issued an alert, based on 27 case reports gathered over a 5-year span, regarding serotonin syndrome resulting from concurrent use of either a selective serotonin-reuptake inhibitor (SSRI) or a selective serotonin/norepinephrine reuptake inhibitor (SNRI) with a triptan. These diagnoses have been subsequently challenged as not meeting validated criteria for serotonin syndrome, in part because the FDA has yet to publicly disseminate important case report data. As a result of the FDA's alert, some clinicians are reluctant or refuse to provide these drugs concomitantly to patients. We believe that withholding these medications due to fears of serotonin syndrome is difficult to justify. In contrast to the small number of case reports, research shows that approximately 700,000 patients annually take SSRIs or SNRIs with triptans and that this drug combination has been effectively used by millions of individuals over the past decade. We encourage healthcare professionals to familiarize themselves with data on serotonin syndrome and to administer SSRIs/SNRIs with triptans when clinically appropriate.

Misdiagnosis of serotonin syndrome as fibromyalgia and the role of physical therapists

BACKGROUND AND PURPOSE

With increased use of serotonergic medications, a condition triggered by serotonin excess within the brain and spinal cord has emerged and may be gaining prevalence. The purposes of this case report are to describe how to identify serotonin syndrome in a patient who is taking citalopram (a selective serotonin reuptake inhibitor) on the basis of signs and symptoms and to promote the ability of physical therapists to recognize such signs and symptoms.

CASE DESCRIPTION

The patient was a 42-year-old woman referred for physical therapy with a diagnosis of fibromyalgia. The physical therapist recognized that the patient's symptoms did not resemble those of fibromyalgia and recommended referral to a neurologist for further diagnostic testing.

OUTCOMES

The patient was referred to a neurologist, who diagnosed serotonin syndrome related to the use of citalopram. The patient was weaned off citalopram and made a successful recovery, with scores on the Oswestry Disability Index decreasing from 70% to 28% at discharge from the physical therapy treatment and to 0% at the 6-month follow-up. The patient has since returned to her prior activity level, which includes skiing, motorcycle riding, and working at her consulting firm.

DISCUSSION

This case report demonstrates how careful evaluation by the physical therapist indicated that signs and symptoms were not consistent with fibromyalgia, and further medical evaluation revealed the actual diagnosis of serotonin syndrome.

Neuroleptic malignant syndrome and serotonin syndrome

This chapter is focused on drug-induced hyperthermia with special regard to use of antipsychotics and antidepressants for the treatment of schizophrenia and major depression, respectively. Neuroleptic malignant syndrome (NMS) develops during the use of neuroleptics, whereas serotonin syndrome is caused mainly by serotoninergic antidepressants. Although both syndromes show various symptoms, hyperthermia is the main clinical manifestation. In this review we describe the historical background, clinical manifestations, diagnosis, and differential diagnosis of these two syndromes based on our observations on the experimental and clinical data.

A systematic review of the serotonergic effects of mirtazapine in humans: implications for its dual action status

A systematic review of published work concerning mirtazapine was undertaken to assess possible evidence of serotonergic effects or serotonin toxicity (ST) in humans, because drug toxicity and interaction data from human over-doses is an useful source of information about the nature and potency of drug effects. There is a paucity of evidence for mirtazapine having effects on any indicator of serotonin elevation, which leads to an emphasis on ST as an important line of evidence. Mirtazapine is compared with its analogue mianserin, and other serotonergic drugs. Although mirtazapine is referred to as a dual-action 'noradrenergic and specific serotonergic drug' (NaSSA) little evidence to support that idea exists, except from initial microdialysis studies in animals showing small effects; those have not subsequently been replicated or substantiated by independent researchers. Also, new data indicate its affinity for Alpha 2 adrenoceptors is not different to mianserin. It appears to exhibit no serotonergic symptoms or toxicity in over-dose by itself, nor is there evidence that it precipitates ST in combination with monoamine oxidase inhibitors, as would be expected if it raises intra-synaptic serotonin levels. Mirtazapine has no demonstrable serotonergic effects in humans and there is insufficient evidence to designate it as a dual-action drug.

A Comparison of the Pharmacokinetics of Oral and Sublingual Cyproheptadine

BACKGROUND

Cyproheptadine is reported to be effective in treating serotonin syndrome. It is only available as an oral preparation and administration after SSRI overdose treated with activated charcoal is problematic. Sublingual administration may circumvent this problem. The pharmacokinetics of sublingual cyproheptadine are not characterized. This study compares the pharmacokinetics of cyproheptadine following oral and sublingual administration.

METHODS

Cross-over, non-blinded, volunteer study using five healthy males. Eight milligrams of oral and sublingual cyproheptadine were administered on separate occasions with a one-week washout period. Sublingual arm subjects were pretreated with 50 g of oral activated charcoal 30 min prior to cyproheptadine, to prevent any gut absorption. Serum cyproheptadine concentration was measured at baseline, 30 min, and 1, 2, 3, 4, 6, 8, and 10 h by liquid chromatography and mass spectroscopy.

RESULTS

Mean C(max) for oral and sublingual were 30.0 microg/L and 4.0 microg/L respectively: mean T(max) were 4 h and 9.6 h; mean AUC were 209 and 25 microg x hr/L. Mean +/- SEM within-subject difference between oral and sublingual C(max) was 25.9 +/- 4.1 (p = 0.003) and AUC was 184 +/- 31 (p = 0.004).

CONCLUSIONS

Serum concentrations after sublingual cyproheptadine are significantly less than after oral administration. At these concentrations, the sublingual route is unlikely to be effective in treating serotonin syndrome.

Psychopharmacohazardology: major hazards of the new generation of psychotherapeutic drugs

Balancing the benefits and risks of prescribing psychotherapeutic drugs requires knowledge of the baseline risks of genetics, lifestyle and morbidity of untreated illness. Superimposed upon these risks are some rare but potentially dangerous, uncomfortable or irreversible hazards of the antipsychotics, mood stabilizers, antidepressants and tranquillizers. Knowledge of these hazards facilitates monitoring and prompt intervention at the earliest sign of problems.

Psychopharmaco-hazardology: major hazards of treating depression and anxiety

Balancing the benefits and risks of prescribing psychotherapeutic drugs requires knowledge of both drug hazards as well as risk of untreated psychiatric illness. Screening for medical illnesses, substance abuse, suicidality, and unusual side effects is essential throughout treatment.

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

The 'atypical' antidepressants comprise a heterogenous class with wide variation in presentation and management during overdose, both when compared with each other and with more traditional agents.Further toxico-epidemiological data are required to make definitive predictions about the clinical effects of most of these agents in overdose. Here, however, we review the available information in a manner intended to benefit both prescribers and clinical toxicologists. Our conclusion is that there can be no generic response by medical practitioners as to the 'safety' of these new antidepressants. Though undoubtedly exhibiting fewer problems in specific areas than some of the older classes of agents (e.g. arrhythmias with tricyclic antidepressants) each nonetheless presents unique safety problems. We experienced great difficulty obtaining accurate information from the manufacturers about the animal toxicity data upon which their recommended human dose limits were set. This highlights the uncertainties involved with too readily making 'safety' claims about these agents. The decision to prescribe 'atypical' antidepressant medications alleged to be both efficacious and safe in overdose involves a medicolegal tension. This tension is between respecting patient autonomy through frank communication of the material risk of overdose and non-disclosure to avoid such harm.

Mirtazapine-induced serotonin syndrome

An 85-year-old woman developed sudden confusion and dysarthria progressing to mutism, orobuccal dyskinesias, generalized tremors worse with activity, ataxia, and rigidity with cog wheeling without high-grade fevers or dysautonomia. These findings were related temporally to the institution of mirtazapine as monotherapy for a major depressive illness with superimposed anxiety disorder. Withdrawal of the agent resulted in early notable clinical resolution with only residual hypertonia after 2 weeks. This is a rare report of serotonin syndrome induced by mirtazapine monotherapy. The hypothesized pathophysiologic mechanism in this case is overstimulation of serotonin (5-hydroxytryptamine or 5-HT) type 1A receptors (5-HT(1A)) in the brainstem and spinal cord in an individual with risk factors for hyperserotoninemia resulting from reduced, acquired endogenous serotonin metabolism.

Serotonin agents in the treatment of acquired brain injury

BACKGROUND

The development of novel serotonin agents has led to an increased use of these medications throughout medical practice. An understanding of the basic pharmacological function of these agents is key to understanding their usefulness. Among persons with brain injury, serotonin agents have been used for the treatment of depression, panic disorder, obsessive-compulsive disorders, agitation, sleep disorders, and motor dysfunction.

CONCLUSION

This article will review the mechanisms, efficacy, and side effects of serotonin agents with a focus on persons with brain injury.

Sleep disturbances and their management in patients with brain injury

OBJECTIVES

Sleep disturbances in people with brain injuries, although quite common, remain a problematic management issue for caregivers. This article will review the architecture of sleep, the assessment of insomnia, and discussion of common medications that may exacerbate the problem. Nonpharmacological management techniques, including stimulus control, sleep restriction, and relaxation therapy, will also be discussed.

MAIN OUTCOME MEASURES

An intensive analysis of pharmacological agents used in treatment, including descriptions of the positive and negative effects of the various classes of drugs (e.g., sedative/hypnotics, antihistamines, dopamine agonists, and stimulants) will be provided.

CONCLUSIONS

These discussions will hopefully assist in the decision-making processes of caregivers managing this unique group of persons with sleep difficulties.

Venlafaxine poisoning complicated by a late rise in creatine kinase: two case reports

Newer anti-depressants are often considered to be safer than more established anti-depressants. However, clinical experience of the effects of these agents in overdose is limited. Here, we present two cases of venlafaxine overdose that were complicated by a delayed rise in plasma creatine kinase. Although the clinical consequences were not serious, physicians should be alerted to the possibility of delayed rhabdomyolysis or serotonin syndrome in patients who have taken venlafaxine in overdose.

Severe serotonin syndrome induced by mirtazapine monotherapy

OBJECTIVE

To document a case of serotonin syndrome (SS) associated with mirtazapine monotherapy, review the previously reported cases of SS associated with this tetracyclic antidepressant, and discuss the possible pathogenic mechanisms leading to this serious adverse drug reaction.

CASE SUMMARY

A 75-year-old man developed agitation, confusion, incoordination, and gait disturbance because of progressive rigidity. Mirtazapine had been started 8 days earlier to control major depression. Physical examination revealed diaphoresis, low-grade fever, hypertension, tachycardia, bilateral cogwheel rigidity, hyperreflexia, tremor, and myoclonus, symptoms and signs that are consistent with severe SS.

DISCUSSION

A review of the cases of SS with implication of mirtazapine as the cause was performed. The possible pathogenic mechanisms leading to this adverse reaction in this patient are also discussed, and pathophysiologic hypotheses are formulated.

CONCLUSIONS

Although mirtazapine offers clinicians a combination of strong efficacy and good safety, we suggest bearing SS in mind when prescribing this drug, especially in frail, elderly patients with underlying chronic conditions. In these patients, it might be more adequate to start mirtazapine therapy at a lower dose (<15 mg/d).