Winnie, ZYBAN is actually an anti-depressant with a generic name of Buproprion; it is also marketed as WELLBUTRIN for psychiatric use. It's well-tolerated, though some patients experience mild stimulation. Fortunately, it has no sexual side effects in comparison to such drugs as Prozac,Zoloft, and Paxil. The FDA approved its use for smoking cessation a few years ago after its wide acceptance historically as one of many anti-depressants.
I've seen mixed results with its use. Smokers HAVE TO be highly motivated to quit IF it is to be effective. It does decrease the oral craving associated with smoking, but so much of cigarette use is psychological.
Good luck to your DH