Switching from Venlafaxine to Duloxetine

Introduction to Switching Protocol

The American College of Cardiology and other guideline societies recommend that venlafaxine 150 mg and duloxetine 60 mg are therapeutically equivalent doses within the same pharmacological class (SNRIs), with balanced inhibition of serotonin and norepinephrine 1
The initial recommended dose of duloxetine is 60 mg/day, with no additional therapeutic benefit demonstrated with doses above 50-60 mg/day, according to the guideline society recommendations 1, 2

Patients should be monitored for withdrawal symptoms, such as dizziness, nausea, headache, irritability, insomnia, diarrhea, anxiety, and fatigue, which typically emerge in the first week and resolve within 1-2 weeks, with a low risk of severe symptoms 2
Blood pressure and heart rate should be measured weekly for the first 2-4 weeks, as both medications can cause sustained hypertension, with special caution in patients with pre-existing cardiac disease 2, 3

The guideline society recommends waiting 4-6 weeks at the therapeutic dose (60 mg/day) before evaluating the efficacy of duloxetine, with limited evidence of additional benefit with higher doses 2
Rare but serious side effects, such as suicidal ideation, behavioral activation, hypomania, mania, sexual dysfunction, seizures, abnormal bleeding, and serotonin syndrome, should be monitored, with gradual tapering of duloxetine when discontinuation is necessary 2, 3