A patient develops linezolid-associated serotonin syndrome when concurrently using sertraline. The mechanism is:
- A Linezolid is a reversible inhibitor of monoamine oxidase A and B, preventing serotonin degradation; combined with an SSRI, serotonin accumulates to toxic levels ✓
- B Linezolid competitively displaces serotonin from platelet storage, causing massive systemic release
- C Linezolid inhibits the serotonin transporter (SERT) directly
- D Linezolid activates 5-HT3 receptors in the gut, causing hyperstimulation
Correct answer: A. Linezolid is a reversible inhibitor of monoamine oxidase A and B, preventing serotonin degradation; combined with an SSRI, serotonin accumulates to toxic levels
Explanation
Linezolid is an oxazolidinone antibiotic that, besides inhibiting 23S rRNA peptidyl transferase centre, is also a weak, reversible, non-selective MAO inhibitor (both MAO-A and MAO-B). MAO-A normally degrades serotonin. When linezolid is combined with serotonergic agents (SSRIs, SNRIs, TCAs, triptans, fentanyl), the combined effect raises synaptic serotonin to toxic levels, producing serotonin syndrome (hyperthermia, clonus, agitation, diaphoresis). This is a class effect; tedizolid has less MAO inhibitory activity.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.