Nausea, somnolence, insomnia, and dizziness are the main side effects, reported by about 10% to 20% of patients.
In a trial for major depressive disorder (MDD), the most commonly reported treatment-emergent adverse events among duloxetine-treated patients were nausea (34.7%), dry mouth (22.7%), headache (20.0%) and dizziness (18.7%), and except for headache, these were reported significantly more often than in the placebo group.
Sexual dysfunction is often a side effect of drugs that inhibit serotonin reuptake. Specifically, common side effects include difficulty becoming aroused, lack of interest in sex, and anorgasmia (trouble achieving orgasm). Loss of or decreased response to sexual stimuli and ejaculatory anhedonia (inability to experience pleasure from activities usually found enjoyable) are also possible. Although usually reversible, there are some who report sexual side effects persisting after the drug has been withdrawn; this is known as post-SSRI sexual dysfunction.[medical citation needed]
Post marketing spontaneous reports
Reported adverse events which were temporally correlated to Cymbalta therapy include rash, reported rarely, and the following adverse events, reported very rarely: alanine aminotransferase increased, alkaline phosphatase increased, anaphylactic reaction, angioneurotic edema, aspartate aminotransferase increased, bilirubin increased, glaucoma, hepatitis, hyponatremia, jaundice,orthostatic hypotension (especially at the initiation of treatment), Stevens–Johnson syndrome, syncope (especially at initiation of treatment), and urticaria.