Major
citalopram × fluvoxamine
SSRI (selective serotonin reuptake inhibitor)×SSRI
Mechanism
Two SSRIs simultaneously – serotonin syndrome without therapeutic purpose. Fluvoxamine also blocks CYP1A2 (a minor citalopram route).
Symptoms
Serotonin syndrome: agitation, confusion, tremor, myoclonus, hyperreflexia. Autonomic features: sweating, tachycardia, hypertension, fever. First signs appear within hours of co-administration.
Management
The combination is not prescribed. When switching SSRIs, allow a 2-week washout. Alternative monotherapy: mirtazapine or agomelatine.