Seen On

DALLAS (CBS 11 News) ― It's called Varenicline. Smokers know it as Chantix. The pill is hailed as a wonder drug to help people quit smoking. But many are coming forward reporting bone-chilling side effects.

It was Labor Day when Carter Albrecht, a local musician, had a few drinks and swallowed his first 1 milligram tablet of Chantix to help him quit smoking. His girlfriend, Ryann Rathbone, met him at a club and they both drove home. Ryann says during the car ride, Carter didn't seem himself. He became abusive and later, delusional. By the time they arrived at the house, Ryann says Carter's behavior had become aggressive. She says he hit her several times. She remembers being curled up on the floor in a fetal position to protect herself when Carter asked, "who did this to you and why are you crying?"

Ryann says he ran out of the house. Moments later, a shot rang out.

Carter was shot and killed while breaking into a neighbor's house.

Family and friends say Carter was never a violent man. Both Ryann and Carter's father feel that Chantix played some role in his death.

This isn't the only incident of people expressing concern about Chantix. Some of the bizarre stories people are reporting:

Deborah in Oregon felt suicidal.

Candace from Arizona felt aggression.

Karen from Maryland says she also had feelings of suicide.

Scott and Monica Mullins used Chantix to stop smoking and after taking the pill, Monica says she had terrible bouts of nausea and vomited all the time. Her husband Scott says he began to have bad dreams and horrible thoughts about ending his life. They stopped taking Chantix.

Chantix is manufactured by Pfizer. CBS 11 accessed the Food and Drug Administration's database of adverse side effects and found thousands of similar and very serious reactions to Chantix. Pfizer's patient information insert for Chantix lists only five "common" side effects. But in a separate insert meant for doctors, some rare and frightening adverse reactions appear listed in 1-millimeter size print. The list includes things like suicidal thoughts, aggression, and neurological and psychiatric disorders.

Chantix went on the market in August 2006. Pfizer tested it on fewer than five thousand people, which is considered normal.

In Europe, the drug is known as Champix. CBS 11 discovered the United Kingdom's Commission on Human Medicines, similar to the FDA, lists Champix on its new drugs under intensive surveillance and discussed a potential signal of a risk of "suicidal thoughts and behaviors" associated with this pill.

But the United Kingdom's Committee also states there is no evidence to suggest the pill increases those risks. Pfizer states the drug is safe and told us "our analysis to date does not suggest a causal association between Chantix and violence." The FDA told us that Chantix is safe and effective when used according to the product's label.

This month Public Citizen, a political watchdog group in Washington D.C., put Chantix on its worst pill list.

The reasoning, according to Public Citizen, is that half of all drug problems arise in the first seven years on the market.

Dallas psychiatrist Bryon Adinoff specializes in addiction. He says he has no problems prescribing the drug and points out that using Chantix or other medicines with alcohol, like Carter Albrecht did, could lead to unpredictable results.

There's no warning to avoid alcohol while taking Chantix, and the pill remains popular among smokers trying to quit. According to Pfizer, "patients on Chantix were 44% more likely to quit smoking at the end of 12 weeks."

There are three million people on Chantix in the United States. Ryann Rathbone used to be one of them. She copes with the pain of her loss by wearing Carter's ring around her neck. The inscription written in Italian says "remember." "I'm convinced - Chantix played a big role," she said. "Nothing else makes sense."

In July, Carter asked Ryann to marry him.

You can report an adverse reaction to this or any other drug by calling the FDA at 1-888-INFO-FDA.

(© MMVII, CBS Broadcasting Inc. All Rights Reserved.)