Call your doctor at once if you have a serious side effect such as: 1  headache with chest pain and severe dizziness, fast or pounding heartbeats, shortness of breath, fainting; 2  diarrhea that is watery or bloody;  fever, swollen glands, body aches, flu symptoms, new or worsening cough;
The maximum daily doses is also slightly different as both Wellbutrin XL and Wellbutrin have a maximum daily dose of 450 mg per day, whereas the maximum dosage for Wellbutrin SR is only 400 mg per day.
Wellbutrin comes in several forms; SR means sustained release, while XL means extended release-there is little difference here. Without the letters SR or XL, plain bupropion is a tablet that releases the drug into the blood stream a little more rapidly than the others.