I was on both at once at one point and switched to just welbutrin. My dose was pretty standard for both and I didn’t have too hard of a time with it. Some brain zaps for a couple days but nothing bad. I actually found welbutrin by itself worked better for me.

I was on both Wellbutrin- the extended release (there are 3 kinds- Regular, ER, and suspended release-known as SR) and lexapro together for many years. I switched from lexapro to Prozac this year. And still on both Wellbutrin and Prozac in increased doses. I do not think you’ll have too much withdrawal. You might have side effects from starting the new medication. My digestive system can sometimes gets wackier( because it’s always wacky) when I change medications in any way. My advice, if you feel side effects or symptoms- stay in touch with your doctor. Also if there are any other medications or supplements/herbs you take I suggest you use the drugs.com interaction checker. Sometimes interactions can be missed so I like to check and if I am concerned I’ll speak to a doctor or pharmacist.

I think most common Wellbutrin interactions/side effects are dizziness, cardiac-like blood pressure or palpitations and side effect of Wellbutrin can be loss of appetite.