Linezolid, an oxazolidinone antibiotic, carries a specific interaction risk when used with serotonergic drugs such as SSRIs. The mechanism for this interaction is:

• A Linezolid inhibits CYP2D6, reducing SSRI metabolism and causing toxicity
• B Linezolid is a reversible inhibitor of monoamine oxidase A, increasing synaptic serotonin ✓
• C Linezolid directly stimulates serotonin 5-HT3 receptors in the CNS
• D Linezolid inhibits serotonin reuptake transporter independent of MAO

Explanation

Linezolid is a weak, reversible inhibitor of monoamine oxidase A (MAO-A), the enzyme primarily responsible for serotonin degradation. When combined with serotonergic agents (SSRIs, SNRIs, tricyclics, tramadol), linezolid's MAO-A inhibition prevents serotonin breakdown, leading to serotonin syndrome manifest as hyperthermia, clonus, agitation, and autonomic instability. This is a recognized contraindication in practice.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.