Mild serotonin syndrome associated with concurrent linezolid and fluoxetine

“A cross-sectional analysis of linezolid in combination with methadone or buprenorphine as a cause of serotonin toxicity.”

Background

Serotonin toxicity (also referred to as serotonin syndrome) results from medications that affect the neurotransmitter serotonin. The antibiotic linezolid and the opioids methadone and buprenorphine are all reported to cause serotonin toxicity, but the degree of risk with use of linezolid in combination with methadone or buprenorphine is unknown.

Methods

We conducted a retrospective cross-sectional analysis of adult patients hospitalized from November 2015 to October 2019 who were administered linezolid in combination with methadone and/or buprenorphine within 24 hours and a subgroup that received the combination for ≥3 days. Cases of serotonin toxicity were identified from the clinical notes in the electronic medical record and were classified as possible or definite based on the clinical record. The Hunter diagnostic criteria were retrospectively applied.

Results

There were 494 encounters in which linezolid was administered concurrently with methadone and buprenorphine. The mean patient age was 42.5 years, and 52.4% of encounters were of female patients. The mean duration of concurrent administration was 1.9 days. There were 106 encounters with a duration of concurrent administration ≥3 days (mean, 5.4 days). Two cases of possible serotonin toxicity and 0 cases of definite serotonin toxicity occurred; neither possible case met the Hunter criteria from the available information. Possible cases occurred in 0.40% of all encounters and 1.89% of encounters with ≥3 days of overlap (upper 1-sided 95% CI, 0.87% and 4.06%).

Conclusions

Serotonin toxicity occurring during the administration of linezolid in combination with methadone and/or buprenorphine occurred rarely among 494 hospital encounters, including 106 encounters with ≥3 days of overlap. Limitations include potential missed diagnoses of serotonin toxicity and short durations of overlap. Further study evaluating the short-term risk of this combination is needed.

Linezolid-induced serotonin syndrome

Linezolid is an oxazolidinone antibiotic, which is a weak, reversible, nonselective monoamine oxidase A and B inhibitor; is known to increase serotonin levels, and has been implicated in the development of serotonin syndrome (SS). There is limited literature on the development of SS with linezolid, when used alone. In this report, we present the case of a 70-year-old female who developed features of SS while being treated with linezolid 600 mg twice daily for pneumonia. The SS in her case was managed with stoppage of linezolid, administration of cyproheptadine, and supportive measures.

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.

A review of the interplay between tuberculosis and mental health

AIMS

Tuberculosis and mental illness share common risk factors including homelessness, HIV positive serology, alcohol/substance abuse and migrant status leading to frequent comorbidity. We sought to generate a comprehensive literature review that examines the complex relationship between tuberculosis and mental illness.

METHODS

A literature search was conducted in MedLine, Ovid and Psychinfo, with further examination of the references of these articles. In total 316 articles were identified. It was not possible to conduct a formal meta-analysis due to the absence of randomised controlled data.

RESULTS

Rates of mental illness of up to 70% have been identified in tuberculosis patients. Medications used in the treatment of common mental illnesses, such as depression, may have significant interactions with anti-tuberculosis agents, especially isoniazid and increasingly linezolid. Many medications used in the treatment of tuberculosis can have significant adverse psychiatric effects and some medications such as rifampicin may reduce the effective doses of anti-psychotics y their enzyme induction actions. Treatment with agents such as cycloserine has been associated with depression, and there have been reported cases of psychosis with most anti-tuberculous agents. Mental illness and substance abuse may also affect compliance with treatment, with attendant public health concerns.

CONCLUSIONS

As a result of the common co-morbidity of mental illness and tuberculosis, it is probable that physicians will encounter previously undiagnosed mental illness among patients with tuberculosis. Similarly, psychiatrists are likely to meet tuberculosis among their patients. It is important that both psychiatrists and physicians are aware of the potential for interactions between the drugs used to treat tuberculosis and psychiatric conditions.

Serotonergic and Adrenergic Drug Interactions Associated with Linezolid: A Critical Review and Practical Management Approach

OBJECTIVE

To describe the evidence for serotonergic and adrenergic drug interactions with linezolid and discuss clinical management strategies.

DATA SOURCES

A literature search of PubMed (1947–November 2012), MEDLINE (1946–November 2012), EMBASE (1974–November 2012), and International Pharmaceutical Abstracts (1970–November 2012) was conducted using the terms linezolid, drug interaction, serotonin syndrome, serotonin toxicity, sympathomimetic, serotonergic agents, and adrenergic agents. Citations of retrieved articles were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

English-language articles describing coadministration of serotonergic or adrenergic agents with linezolid to humans were included. Studies published only in abstract form were excluded.

DATA SYNTHESIS

One prospective study, 6 retrospective studies, and 24 case reports were identified describing a serotonergic or adrenergic drug interaction. Incidence of serotonin syndrome in patients on linezolid and serotonergic agents ranged between 0.24% and 4%. Serotonergic agents determined to have probable (according to the Horn Drug Interaction Probability Scale) linezolid interactions in case reports included meperidine, citalopram, escitalopram, fluoxetine, paroxetine, sertraline, duloxetine, and venlafaxine. Serotonergic agent dose and duration of coadministration with linezolid did not appear to influence the occurrence of serotonin syndrome. Adrenergic medication coadministration was associated with a possible drug interaction as determined by the Horn Drug Interaction Probability Scale but did not appear to result in clinically significant drug interactions with linezolid.

CONCLUSIONS

Linezolid-associated serotonergic drug interactions occur more commonly than adrenergic interactions. Serotonergic interactions considered probable according to the Horn Drug Interaction Probability Scale do not appear to correlate with drug dosage; time of onset ranges from <1 to 20 days, and effect resolves in <1 to 5 days after discontinuation of offending agents. If coadministration of linezolid and a serotonergic agent cannot be avoided, clinicians should be aware of the symptoms and management of serotonergic toxicity; close monitoring is recommended and additional serotonergic agents should not be used. While adrenergic drug interactions with linezolid are less common in clinical practice, monitoring for signs of hypertension remains important.

Clinical relevance of linezolid-associated serotonin toxicity

OBJECTIVE

To evaluate and review the literature surrounding serotonin toxicity in patients receiving linezolid and determine the clinical relevance of this reaction.

DATA SOURCES

Literature was accessed via MEDLINE/PubMed and Google Scholar (both through February 2013) using the search terms linezolid, serotonin syndrome, serotonin toxicity, and adverse reaction.

STUDY SELECTION AND DATA EXTRACTION

Relevant case reports, retrospective studies, surveys, and review articles were included. Bibliographies of all relevant articles were reviewed for additional sources.

DATA SYNTHESIS

Linezolid exhibits mild, nonselective inhibition of monoamine oxidase and has been associated with serotonin toxicity when used in combination with other serotonergic agents. Based on published reports, the incidence of linezolid-associated serotonin toxicity is between 0.54% and 18.2%. Our review identified 32 documented cases, including 3 fatalities. Most cases occurred in patients concurrently receiving selective serotonin reuptake inhibitors. Receipt of multiple agents with serotonergic activity seems to increase the risk of serotonin toxicity. Both onset and resolution of symptoms varied from hours to days.

CONCLUSIONS

Current Food and Drug Administration recommendations to avoid the use of linezolid in patients receiving select serotonergic agents highlight the need to carefully balance the risk/benefit ratio in this situation. Although linezolid has been available for 12 years, reports of serotonin toxicity with this agent are uncommon. While clinicians should be aware of this potentially severe interaction and closely monitor patients who are receiving linezolid in combination with serotonergic agents, our findings show that linezolid is not contraindicated in this situation.

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.

Miscellaneous central nervous system intoxicants

The topic of central nervous system intoxicants encompasses a multitude of agents. This article focuses on three classes of therapeutic drugs, with specific examples in which overdoses require admission to the intensive care unit. Included are some of the newer antidepressants, the atypical neuroleptic agents, and selected anticonvulsant drugs. The importance of understanding pertinent physiology and applicable supportive care is emphasized.

Pharmacokinetic drug interactions of antimicrobial drugs: a systematic review on oxazolidinones, rifamycines, macrolides, fluoroquinolones, and Beta-lactams

Like any other drug, antimicrobial drugs are prone to pharmacokinetic drug interactions. These drug interactions are a major concern in clinical practice as they may have an effect on efficacy and toxicity. This article provides an overview of all published pharmacokinetic studies on drug interactions of the commonly prescribed antimicrobial drugs oxazolidinones, rifamycines, macrolides, fluoroquinolones, and beta-lactams, focusing on systematic research. We describe drug-food and drug-drug interaction studies in humans, affecting antimicrobial drugs as well as concomitantly administered drugs. Since knowledge about mechanisms is of paramount importance for adequate management of drug interactions, the most plausible underlying mechanism of the drug interaction is provided when available. This overview can be used in daily practice to support the management of pharmacokinetic drug interactions of antimicrobial drugs.

Linezolid interaction with serotonin reuptake inhibitors: report of two cases and incidence assessment

BACKGROUND

Prompted by the advent of potentially life-threatening neuromuscular symptoms following initiation of linezolid therapy in two patients receiving treatment with a serotonin reuptake inhibitor antidepressant, an evaluation was conducted to determine the incidence and characteristics of symptomatic serotonin toxicity among hospitalized patients receiving combined treatment with these medications.

METHODS

Patients admitted between January 1, 2006 and August 30, 2008 who received linezolid concurrently with citalopram or escitalopram were identified and their medical records were examined. Patients were judged to have serotonin toxicity if their records contained documentation of clinical evidence adequate to fulfill requisites of the Hunter Serotonin Toxicity Criteria. Severity of serotonin-related symptoms was graded according to previously established criteria.

RESULTS

During the period of observation, 24 patients received concurrent treatment with linezolid and citalopram or escitalopram. Of these, one patient (4%) treated with citalopram met evidentiary requirements for diagnosis of serotonin toxicity. The severity of symptoms in this patient was graded as mild. No evidence of serious harm related to a possible drug interaction was identified.

CONCLUSIONS

Severe symptoms associated with serotonin toxicity were shown to be uncommon in patients receiving linezolid and selected serotonin reuptake inhibitors. Nonetheless, serious interaction-related toxicity has been observed at our institution and reported in detail by others. Accordingly, concurrent use of these medications is categorized as contraindicated. Alternative antimicrobial therapy should be instituted in most cases. If no suitable alternative is available, recipient patients should be hospitalized for expectant observation and rigorous monitoring.

Serotonergic antidepressants and linezolid: a retrospective chart review and presentation of cases

OBJECTIVE

To report the results from a retrospective chart review looking at the combination of linezolid and serotonergic antidepressants and to report two cases of serotonin syndrome which were identified at our hospital.

CASE SUMMARY

During the retrospective chart review one case of serotonin syndrome was identified. A 65-year-old female was receiving escitalopram for the treatment of depression prior to admission. Linezolid therapy was initiated on admission and two days later the patient had a tonic-clonic seizure. Escitalopram was discontinued and the patient did not have any further seizure activity. In a second case, a 37-year-old male was receiving citalopram during hospitalization and was started on concomitant linezolid. The patient had myoclonus and was observed to be tremulous throughout therapy with linezolid. Ten days after discontinuation of linezolid the patient continued to have symptoms until the withdrawal of citalopram. The Naranjo probability scale scores the first case as possibly related and the second case as probably related to the combination.

DISCUSSION

It has been well documented in the literature that the combination of linezolid and serotonergic antidepressants may cause serotonin syndrome. In this retrospective chart review only one patient of 53 (1.8%) had symptoms highly suggestive of serotonin syndrome. A second patient continued to have symptoms of serotonin syndrome even after withdrawal of linezolid.

CONCLUSIONS

This retrospective review and subsequent case reports confirm the rare, but serious, potential of serotonin syndrome associated with the combination of linezolid and serotonergic antidepressants.