MajorSNRI×Selective serotonin reuptake inhibitors
Updated · Methodology
Mechanism
Fluoxetine is a potent CYP2D6 inhibitor; duloxetine is minorly metabolised by CYP2D6. Additive serotonergic load with dual SSRI/SNRI dosing.
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 from fluoxetine to duloxetine, allow a 5-week washout (due to norfluoxetine); from duloxetine 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.
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Sources
- FDA: Cymbalta section 7 (2017)– ; DailyMed setid 2f7d4d67-10c1-4bf4-a7f2-c185fbad64ba