Generic Zyban side effects are generally not serious. They are commonly exhibited in the form of headaches, insomnia, vomiting, shaking, changes in appetite or weight, skin problems, decreased sexual desire, constipation, or nausea. More serious reactions that will need to be reported to the appropriate medical personnel are as follows: hallucinations, confusion, swollen glands, skin blistering or peeling, seizures, mood shifts, unexplained behavior, increased aggressiveness, or thoughts of suicide. Generic Zyban side effects may differ from person to person and the dosage level may need to be adjusted to avoid these reactions.