All of the following anti-depressant drugs are serotonin and norepinephrine reuptake inhibitors except one. Which one is the exception?

Sertraline (Zoloft)

Venlafaxine (Effexor)

Nortriptyline (Pamelor)

Desipramine (Norpramin)

Desvenlafaxine (Pristiq)

Duloxetine (Cymbalta)