Critical
citalopram × Linezolid
SSRI (selective serotonin reuptake inhibitor)×Oxazolidinone antibiotic
Mechanism
Citalopram (SSRI) raises synaptic serotonin. Linezolid reversibly inhibits MAO. Co-administration sharply amplifies serotonergic transmission. The FDA carries a boxed warning.
Symptoms
Serotonin syndrome: agitation, confusion, tremor, myoclonus, hyperreflexia, dilated pupils. Autonomic features: profuse sweating, tachycardia, hypertension, fever above 38.5 °C. Severe cases progress to seizures, rhabdomyolysis, disseminated intravascular coagulation, and death. First signs appear within hours of concurrent dosing.
Management
The combination is not prescribed. Stop citalopram at least 2 weeks before linezolid. Alternative antibiotics: vancomycin, daptomycin, ceftaroline by susceptibility.