MajorSSRI×SNRI (serotonin-norepinephrine reuptake inhibitor)
Updated · Methodology
Mechanism
Fluvoxamine blocks CYP1A2 (a minor venlafaxine metabolic route). Venlafaxine plasma levels rise modestly. Plus additive serotonergic load.
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 antidepressants, allow a 1-week washout. Alternative for augmentation: mirtazapine or agomelatine.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Effexor + Zoloft drug interactions (2017)– ; DailyMed setid c848a5d8-ba94-4c84-80e3-0bf35fb8e32e
- AEMPS: Ficha técnica: Venlafaxina (nº registro 67542), sección 4.5 (2024)– AEMPS, CIMA, nº registro 67542, revisión 03/2024, sección 4.5