Although you don't have these contra-indications for using Zyban, you may still experience side effects, The most common are dry mouth and insomnia (usually dealt with by taking the second daily dose no later than 4pm). As do most side-effects, these usually abate in a few days to a week. Agitation is sometimes a side effect of Zyban, but it usually diminishes as the user becomes accustomed to it. Most ex-smokers who quit smoking blame Zyban for what are actually withdrawal symptoms. Check with your doctor about the risks and usage instructions for Zyban.
Source: Zyban (buproprion hydrochloride) Sustained Release Tablets Prescribing Information. GlaxoSmithKline, Research Triangle Park, NC. 3/2003