Some side effects of Zyban, while not as common, are potentially serious and should be reported to your healthcare provider. These include but are not limited to:
Extreme elation or feelings of happiness that may switch back and forth with a depressed or sad mood
Other unusual changes in behavior
Hallucinations
A rapid heart rate
Chest palpitations
Difficulty sleeping
Feelings of jitteriness or restlessness
Signs of an allergic reaction, including:
Unexplained rash
Hives
Itching
Unexplained swelling
Wheezing
Difficulty breathing or swallowing.
Rare Zyban Side Effects
Rare Zyban side effects occur in less than 1 percent of people taking the drug. Because these side effects are so uncommon, it is difficult to tell whether they are due to the medication or something else.
Some of these rare side effects include but are not limited to: