Studies show no extra risk with Pfizer smoking drug

Smokers who take Pfizer's pill Chantix to help them quit do not have a higher risk of being hospitalized for psychiatric events such as depression, compared with nicotine patches, according to studies reported on Monday.

Users of Pfizer's non-nicotine pill have reported agitation, depression and suicidal thoughts, and, in clinical trials, the pill was linked to nightmares.

Psychiatric symptoms have occurred in people without a history of mental illness and have worsened in people who already had mental illness, the FDA has said.

Although investors initially had high hopes for the drug, called Champix in Europe, reports of psychiatric effects have hampered sales growth.

The Food and Drug Administration released its review of two studies which compared Chantix to standard nicotine replacement therapy such as the Nicoderm nicotine patch from GlaxoSmithKline.

CHANTIX is a non-nicotine prescription medicine specifically developed to help adults 18 and over quit smoking. Over 7 million people in the U.S. have already been prescribed CHANTIX.

How is CHANTIX different from other smoking cessation products?

CHANTIX does not contain nicotine. It works in two ways. It targets nicotine receptors in the brain, attaches to them, and blocks nicotine from reaching them. It is believed that CHANTIX also activates these receptors, causing a reduced release of dopamine compared to nicotine.

It's recommended that you begin your CHANTIX treatment a week before you stop smoking completely. This gives CHANTIX a chance to build up in your body. You may smoke during the first week of your CHANTIX treatment, but you should stop smoking completely on Day 8 of your treatment.

However, the FDA said the studies had limitations, and it would keep a restrictive "black box" warning on the smoking-cessation aid, advising about psychiatric side effects.

The drug has also been linked to a small increase in heart risk for those who already have heart problems, the FDA said in June.

"Overall, FDA has determined that the current warnings in the Chantix drug label, based on postmarketing surveillance reports, remain appropriate," the agency said in a statement.

Chantix Side Effects As with most prescription and non-prescription medication, Chantix may cause side effects.

Chantix patients have reported a variety of side effects including nausea, headache, sleep difficulties (insomnia, vivid or strange dreams), constipation and gas. If these symptoms persist or if they bother you, let you doctor know.

Other more serious side effects such as suicidal thoughts, depression and behavioral changes have been reported as well. It's important to report these symptoms to your doctor. Your family or others around you may notice these effects before you notice them yourself.