Zyban is a non-nicotine aid to smoking cessation. It is chemically unrelated to nicotine or other agents used in the treatment of nicotine addiction. It is developed as an antidepressant and is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitor, or other known antidepressant agents. It decreases cravings and withdrawal symptoms of smoking.
Common side effects of Zyban include dry mouth and difficulty sleeping. Other less common side effects dizziness, difficulty concentrating, upset stomach, anxiety, constipation, tremors, or skin rashes. There is also a small risk of having seizures, serious or unusual changes in mood, an liver damage.
The use of Zyban has led to lawsuits involving side effects such as birth defects, suicidal behavior, and psychiatric problems. The drug also has a black box warning stating that it may cause changes in behavior, including depressed mood, hostility and suicidal thoughts.