Trying to quit smoking and feel like running into traffic, killing yourself or offing your partner, boss or children? It may be that drug you're taking to help you kick the habit.

The Food and Drug Administration on Wednesday announced it has ordered the makers of the prescription anti-smoking medications Zyban and Chantix (also known by their pharmaceutical names bupropion and varenicline) to warn patients that taking the drugs may cause changes in behavior and mood, including hostility, agitation, depression and suicidal thoughts or behavior. The new warnings will be included in a "black box" intended to alert consumers to important side effects of a drug.

Bupropion is also marketed as Wellbutrin, an antidepressant. In July 2005, the FDA issued a public health advisory warning that Wellbutrin appeared to increase the incidence of suicidal thinking in adults. And in November 2007, the FDA issued a preliminary warning that taking Chantix appeared to increase the risk of suicidal thoughts and behavior.

Both medications were approved by the FDA after their manufacturers presented evidence that taking these drugs increased a smoker's likelihood of successfully quitting the habit. But there are many other ways to stop smoking, all of them laid out here (or call [800] QUIT-NOW). Thinking about quitting cold turkey -- no pills, gums, patches or excuses? Here's a site for you too.

-- Melissa Healy