MajorSelective serotonin reuptake inhibitors (SSRIs)×Selective serotonin reuptake inhibitors
Updated · Methodology
Mechanism
Fluoxetine belongs to the same class, and its SmPC warns about serotonergic reactions when it is combined with other serotonergic agents. Two SSRIs bring no added benefit, while the serotonergic effect stacks.
Symptoms
Serotonin syndrome: agitation, confusion, tremor, myoclonus, hyperreflexia, sweating, diarrhoea, tachycardia, and in severe cases hyperthermia and rigidity. Symptoms usually appear within a day of adding the second drug or raising the dose. In patients with cardiac risk factors QTc is tracked separately.
Management
Stopping fluoxetine does not end the interaction at once: its SmPC gives a half-life of 4-6 days, and 4-16 days for the active metabolite norfluoxetine. A switch is measured in weeks, and the same label requires this to be taken into account when changing antidepressant.
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: Lexapro (escitalopram) prescribing information (2023)– FDA label, Allergan, Inc., DailyMed setid 13bb8267-1cab-43e5-acae-55a4d957630a, revised 10/2023, sections 4, 5.2 and 7
- AEMPS: Ficha técnica de Cipralex 10 mg (escitalopram) (2026)– AEMPS CIMA, nregistro 65230, revisión 03/2026, secciones 4.3 y 4.5
- AEMPS: Ficha técnica de Luramon 20 mg (fluoxetina) (2024)– AEMPS CIMA, nregistro 64970, revisión 05/2024, secciones 4.4, 4.5 y 5.2