Introduction
Linezolid is an oxazolidinone antibiotic against Methicillin resistant
Staphylococcus aureus (MRSA), Vancomycin-resistant Enterococcus (VRE)
and Drug resistant Streptococcus pneumoniae (DRSP) infections. The
structure of linezolid is similar to a selective reversible monoamine
oxidase inhibitor (MAO-A) toloxatone that used for depression treatment
[1].
Regarding this structure–activity relationship similarities between
Linezolid and toloxatone, this antibiotic has non-selective MAO-A
inhibition properties [2]. Some drugs
including SNRIs, TCAs, SSRIs, stimulants and opioid analgesics such as
tramadol, meperidine, methadone and dextromethorphan increase serotonin
levels and interact with linezolid [3,
4].The use of linezolid with this drugs
increase concentrations of serotonin in the central nervous system and
result in serotonin syndrome [1].
Serotonin syndrome (SS) is a rare and potentially fatal condition that
was first reported by Mitchell [5] and
caused by excessive stimulation of serotonin receptor in nervous system.
Features of this syndrome include mental status alteration such as
delirium, anxiety and confusion, autonomic stimulation for example
hyperthermia, tachycardia, tremor, and neuromuscular abnormalities like
myoclonus and rigidity [3]. The main
cause of serotonin syndrome is drugs that increase the level of
serotonin in CNS [6]. Serotonin
syndrome can develop less than 24 hours of ingestion certain medication
[6, 7].
In searches, we found only one case report has described serotonin
syndrome with linezolid and methadone
[8]. We describe a case of SS in
60-year-old drug-addict man who admitted to emergency department.