Major
Diazepam × fluvoxamine
Anxiolytics. Benzodiazepine derivatives×SSRI
Mechanism
Fluvoxamine blocks CYP2C19 and CYP3A4 – both diazepam metabolic routes. Diazepam plasma levels rise 2-fold, with stronger and longer effect.
Symptoms
Marked sedation, drowsiness, ataxia. In older patients: fall and fracture risk. Symptoms appear within 3–5 days.
Management
Halve the diazepam dose when combined. Alternative benzodiazepines without CYP dependence: lorazepam or oxazepam (glucuronidated). Alternative antidepressants without CYP2C19/CYP3A4 effect: sertraline or agomelatine.