Can drowsiness occur with Bupropion?

Yes, it is possible to experience drowsiness with Bupropion, although it tends to cause insomnia for most people. If you are experiencing this side effect, you could try taking it before bedtime instead of in the morning to see if it helps. As for your nasal symptoms, it is unlikely that they are related to taking Bupropion, but it is not impossible. Have you tried using a nasal wash, like Sinus Rinse? With the beginning of spring approaching, it could also be the start of seasonal allergies. Do you have a history of seasonal allergies? Do you have any other symptoms?