Major
duloxetine × fluvoxamine
SNRI×SSRI
Mechanism
Dual risk. Fluvoxamine is a potent CYP1A2 inhibitor, the main duloxetine metabolic route. Duloxetine plasma levels rise 6-fold. 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. Choose one antidepressant: duloxetine for pain syndromes, fluvoxamine for obsessive-compulsive disorder. For augmentation, add mirtazapine.
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.