MajorSelective serotonin reuptake inhibitors×SNRI (serotonin-norepinephrine reuptake inhibitor)
Updated · Methodology
Mechanism
SSRI + SNRI – serotonin syndrome. Fluoxetine is also a potent CYP2D6 inhibitor and raises venlafaxine levels.
Symptoms
Serotonin syndrome: agitation, confusion, tremor, myoclonus, hyperreflexia. Autonomic features: sweating, tachycardia, fever.
Management
The combination is not prescribed. When switching from fluoxetine to venlafaxine, allow at least 5 weeks of washout (due to norfluoxetine). From venlafaxine to fluoxetine, 1 week.
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 XR (venlafaxine) prescribing information (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