Zyban Sustained-Release Tablets have been approved for use as a smoking cessation treatment. It is the first nicotine-free prescription medicine available. It is also the first smoking cessation treatment available in tablet form. Zyban will be available by prescription approximately July 1997.
In addition, the medication includes a patient support program Zyban Advantage Plan--at no additional patient cost. The plan provides additional support and specific smoking cessation techniques.
The effectiveness of Zyban as an aid to smoking cessation was demonstrated in two placebo-controlled, double-blind studies. Over 1,500 chronic smokers who smoked at least 15 cigarettes a day participated in these studies. In one study, Zyban was compared to placebo; in the other study, Zyban was evaluated versus placebo, a nicotine patch (Habitrol (R)(1)), and in combination with the patch. In both studies, all patients received brief individual smoking cessation counseling.
In the study involving the patch, patients treated with Zyban had significantly higher 4-week quit rates than those treated with the patch. Patients treated with the combination of Zyban and the patch had significantly higher quit rates than those treated with the patch alone. Quit rates with combination therapy, while higher, were not statistically higher than quit rates with Zyban alone. The 4-week quit rates from this study were 23% for placebo; 36% for the patch; 49% for Zyban; and 58% for the combination of Zyban and the patch.
For many patients, treatment with Zyban reduced withdrawal symptoms. Withdrawal symptoms showing the most pronounced reductions were: irritability, frustration or anger, anxiety, difficulty concentrating, restlessness, and depressed mood or negative affect. In patients treated with Zyban there was also evidence of a reduction in craving for cigarettes or urge to smoke.
The most common side effects associated with the use of Zyban are dry mouth and insomnia. These side effects are reported to be generally mild, and often disappear after a few weeks. The use of Zyban is also associated with a dose-dependent risk of seizure. Higher than recommended doses should not be prescribed.
Zyban should not be used in people who are already taking Wellbutrin(R), Wellbutrin(R) SR, or any other medication that contains bupropion. It should also not be used in people who are taking or have recently taken a monoamine oxidase inhibitor (MAOI). Zyban should not be used in patients with a seizure disorder who have a history, or are currently diagnosed with bulimia or anorexia nervosa.
Currently, it is unclear how Zyban works. However, it does affect noradrenergic and/or dopaminergic mechanisms in the brain, which have been implicated as pathways of nictotine addiction.