Serotonin Syndrome Caused by Fentanyl and Methadone in a Burn Injury

Serotonin syndrome due to concomitant use of linezolid and methadone

Serotonin syndrome is a potentially life-threatening adverse drug reaction typically caused by a single or combination of two or more medications with serotonergic properties due to increased serotonin release. Our case is a 60-year-old drug-addict man who was admitted to the poisoning department of Loghman hospital with methadone poisoning. On the fifth day of hospitalization and after initiating the linezolid treatment for VAP, the patient began to run a fever with agitation, tremor, spontaneous clonus movement in the hands, and tachycardia. Due to patients' manifestations and after ruling out other diagnoses, serotonin syndrome was confirmed with the possibility of concomitant use of linezolid and methadone. Linezolid administration was promptly discontinued, and vancomycin therapy was initiated (1000 mg twice a day intravenously). Supportive therapies were performed. Finally, tremor, rigidity, and clonus movement disappeared within 48 h.

Preoperative Management of Medications for Neurologic Diseases: Society for Perioperative Assessment and Quality Improvement Consensus Statement

Neurologic diseases are prevalent in patients undergoing invasive procedures; yet, no societal guidelines exist as to best practice in management of perioperative medications prescribed to treat these disorders. The Society for Perioperative Assessment and Quality Improvement tasked experts in internal medicine, anesthesiology, perioperative medicine, and neurology to provide evidence-based recommendations for preoperative management of these medications. The aim of this review is not only to provide consensus recommendations for preoperative management of patients on medications for neurologic disorders, but also to serve as an educational guide to perioperative clinicians. While, in general, medications for neurologic disorders should be continued preoperatively, an individualized approach may be needed in certain situations (eg, holding anticonvulsants on day of surgery if electroencephalographic mapping is planned during epilepsy surgery). Pertinent interactions with commonly used drugs in anesthesia practice, as well as considerations for targeted laboratory testing or perioperative drug substitutions, are addressed as well.

Preoperative Management of Medications for Psychiatric Diseases: Society for Perioperative Assessment and Quality Improvement Consensus Statement

There is a lack of guidelines for preoperative management of psychiatric medications leading to variation in care and the potential for perioperative complications and surgical procedure cancellations on the day of surgery. The Society for Perioperative Assessment and Quality Improvement identified preoperative psychiatric medication management as an area in which consensus could improve patient care. The aim of this consensus statement is to provide recommendations to clinicians regarding preoperative psychiatric medication management. Several categories of drugs were identified including antidepressants, mood stabilizers, anxiolytics, antipsychotics, and attention deficit hyperactivity disorder medications. Literature searches and review of primary and secondary data sources were performed for each medication/medication class. We used a modified Delphi process to develop consensus recommendations for preoperative management of individual medications in each of these drug categories. While most medications should be continued perioperatively to avoid risk of relapse of the psychiatric condition, adjustments may need to be made on a case-by-case basis for certain drugs.

Perioperative Serotonin Syndrome Manifesting as Gastrocnemius Myofasciculations: A Case Report

In perioperative settings where a patient under general anesthesia, presentation of serotonin syndrome might be far from the "classical" description of this potentially fatal condition. A patient who manifested signs of serotonin toxicity during an intravenous anesthetic, remifentanil, is presented. At the time of surgery, the patient was being treated with tramadol for pain management. The patient displayed myofasciculations on both gastrocnemius muscles confirmed electromyographically. All other conventional signs of serotonin syndrome were absent except hypotension and nystagmus. A presumptive diagnosis of serotonin syndrome was made intraoperatively. The symptoms resolved once remifentanil infusion was discontinued in the operating room without incident. Mild-to-moderate perioperative serotonin syndrome may manifest with myofasciculations in gastrocnemius muscles in the settings of no neuromuscular blockade. In spinal surgeries involving intraoperative EMG monitoring, the neuromonitoring team should be aware of this presentation and include serotonin syndrome in the differential diagnosis of unexplained EMG activity.

Serotonin Syndrome Developing Immediately after the Initiation of Low-Dose Methadone Therapy: A Case Report

We present a case in which serotonin syndrome developed immediately after the initiation of low-dose methadone following an increase in oxycodone dose and the initiation of duloxetine. The symptoms of serotonin syndrome were alleviated and later disappeared upon cessation of methadone alone. The case was a 47-year-old woman with a desmoid tumor. The administration of duloxetine (20 mg/day) was initiated while the patient took oxycodone sustained-release tablets (40 mg/day). The following day, excessive perspiration, chills, and tremors appeared after the initiation of 15 mg/day methadone. Discontinuation of methadone led to an alleviation of the symptoms which completely disappeared 3 days later. The results suggest that low-dose methadone can trigger serotonin syndrome as early as after the first dose. Thus, it is important to be aware of the risks and to immediately take action if symptoms appear.

A 5-year single-centre retrospective study of potential drug interactions in burns inpatients with psychiatric comorbidities

INTRODUCTION

Burns patients with psychiatric comorbidities may be at increased risk of harm from drug interactions. We aimed to identify the most common classes of drug involved, the potential clinical effects and any clinical evidence for their occurrence.

METHODS

The International Burn Injury Database was used to identify all admission episodes for patients with a psychiatric comorbidity over a 5-year period at an adult regional burns unit. For this group, all drugs administered were categorised as either a new or continuing medication. Following this, an established online tool was used to screen for potential interactions between drugs. Where one was identified, a retrospective notes review was used to investigate whether it had occurred clinically.

RESULTS

Ninety-one admission episodes were identified and records were available for 60 of these. In total, 145 incidences of severe potential interactions were identified (89 between a new drug and a continuing drug and 56 between two new drugs). The most frequently involved continuing drugs with the potential for interaction were neurotransmitter reuptake-inhibiting antidepressants and mirtazapine, while the most common new drugs identified were ondansetron, fentanyl and tramadol. The most frequently identified potential consequence of interactions were serotonin syndrome, arrhythmias and hypokalaemia. Clinically, there was minimal evidence for any interaction.

CONCLUSION

We have found many potential severe interactions in this patient group and psychotropic drugs were more commonly implicated than other drug classes. However, there was little evidence of the clinical manifestations of interaction. Serious drug interactions in burns patients are likely rare, but clinicians should be aware of the most likely drugs involved and the possible sequelae.

The anaesthetist, opioid analgesic drugs, and serotonin toxicity: a mechanistic and clinical review

Most cases of serotonin toxicity are provoked by therapeutic doses of a combination of two or more serotonergic drugs, defined as drugs affecting the serotonin neurotransmitter system. Common serotonergic drugs include many antidepressants, antipsychotics, and opioid analgesics, particularly fentanyl, tramadol, meperidine (pethidine), and methadone, but rarely morphine and other related phenanthrenes. Symptoms of serotonin toxicity are attributable to an effect on monoaminergic transmission caused by an increased synaptic concentration of serotonin. The serotonin transporter (SERT) maintains low serotonin concentrations and is important for the reuptake of the neurotransmitter into the presynaptic nerve terminals. Some opioids inhibit the reuptake of serotonin by inhibiting SERT, thus increasing the plasma and synaptic cleft serotonin concentrations that activate the serotonin receptors. Opioids that are good inhibitors of SERT (tramadol, dextromethorphan, methadone, and meperidine) are most frequently associated with serotonin toxicity. Tramadol also has a direct serotonin-releasing action. Fentanyl produces an efflux of serotonin, and binds to 5-hydroxytryptamine (5-HT)_1A and 5-HT_2A receptors, whilst methadone, meperidine, and more weakly tapentadol, bind to 5-HT_2A but not 5-HT_1A receptors. The perioperative period is a time where opioids and other serotonergic drugs are frequently administered in rapid succession, sometimes to patients with other serotonergic drugs in their system. This makes the perioperative period a relatively risky time for serotonin toxicity to occur. The intraoperative recognition of serotonin toxicity is challenging as it can mimic other serious syndromes, such as malignant hyperthermia, sepsis, thyroid storm, and neuroleptic malignant syndrome. Anaesthetists must maintain a heightened awareness of its possible occurrence and a readiness to engage in early treatment to avoid poor outcomes.

Drug Interactions in Neurocritical Care

Drug-drug interactions (DDIs) are common and avoidable complications that are associated with poor patient outcomes. Neurocritical care patients may be at particular risk for DDIs due to alterations in pharmacokinetic profiles and exposure to medications with a high DDI risk. This review describes the principles of DDI pharmacology, common and severe DDIs in Neurocritical care, and recommendations to minimize adverse outcomes. A review of published literature was performed using PubMed by searching for 'Drug Interaction' and several high DDI risk and common neurocritical care medications. Key medication classes included anticoagulants, antimicrobials, antiepileptics, antihypertensives, sedatives, and selective serotonin reuptake inhibitors. Additional literature was also reviewed to determine the risk in neurocritical care and potential therapeutic alternatives. Clinicians should be aware of interactions in this setting, the long-term complications, and therapeutic alternatives.

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.

Outpatient intravenous multimodal elastomeric pump with methadone in ambulatory surgery

BACKGROUND AND OBJECTIVE

Analgesia in Ambulatory Surgery (AS) needs to evolve in parallel with surgical complexity. We designed a study to try to improve analgesia in painful surgery using an intravenous elastomeric pump. As a novelty, methadone was included.

PATIENTS AND METHODS

An observational study, physical status ASA I-II, underwent ambulatory surgeries with moderate-severe postoperative pain. Analgesia was administered for 48h by an intravenous multimodal elastomeric pump (methadone, tramadol, dexketoprofen and ondansetron at low doses). Visual Analogue Scale (VAS) at rest and movement were evaluated at 24 and 48h. Andersen Scale, Lattinen Test, rescue analgesia and side-effects were recorded at 24h after surgery.

RESULTS

We included 73 patients: 37% abdominal wall surgery, 30% hemorrhoidectomies and 33% perineal surgery. Median VAS score at rest and movement were 0 and 3 at 24h, and 0 and 2 at 48h. At 24h, Andersen's Scale score was ≤1 in 89%, and Lattinen Test ≤6 in 90% of patients. Rescue medication was administered in 30% of patients. Two patients had vomiting at 24 and 48h. Minor catheter and pump dysfunctions were observed in 8% of patients.

CONCLUSIONS

Multimodal analgesia with intravenous methadone administered by elastomeric perfusion at home is effective and safe. However, monitoring is needed to diagnosis dysfunction of devices.

Adverse Drug Reactions in the Intensive Care Unit

Adverse drug reactions (ADRs) are undesirable effects of medications used in normal doses [1]. ADRs can occur during treatment in an intensive care unit (ICU) or result in ICU admissions. A meta-analysis of 4139 studies suggests the incidence of ADRs among hospitalized patients is 17% [2]. Because of underreporting and misdiagnosis, the incidence of ADRs may be much higher and has been reported to be as high as 36% [3]. Critically ill patients are at especially high risk because of medical complexity, numerous high-alert medications, complex and often challenging drug dosing and medication regimens, and opportunity for error related to the distractions of the ICU environment [4]. Table 1 summarizes the ADRs included in this chapter.