In a safety announcement, the US Food and Drug Administration have updated the label for the prescription smoking cessation medicine Chantix, warning that it could change the way the body reacts to alcohol and on rare occasions lead to seizures.

Cigarette with pills.Share on Pinterest
In 2013, around 1.2 million Americans were treated with the smoking cessation medicine Chantix, the FDA state.

Pfizer, the manufacturer of Chantix (varenicline), submitted a case series to the Food and Drug Administration (FDA) which was reviewed alongside reported cases of patients experiencing adverse reactions to the drug from the FDA Adverse Event Reporting System (FAERS) database.

Chantix is a widely-used smoking cessation medicine approved for use by the FDA in 2006. The FDA state that in 2013, an estimated 1.2 million patients received a dispensed prescription for Chantix from outpatient retail pharmacies in the US.

“In clinical trials, Chantix increased the likelihood of quitting smoking and ‘staying quit’ for as long as 1 year compared to treatment with a placebo, an inactive treatment,” write the FDA.

The National Cancer Institute (NCI) report that tobacco use is the leading cause of preventable illness and death in the US. Cigarette smoking alone causes approximately 443,000 death per year, including an estimated 49,000 deaths attributable to secondhand smoke exposure.

Due to the serious health problems that can be caused by smoking, such as cancer and cardiovascular disease, Chantix could be an important medication that protects thousands of Americans from chronic health problems. The updated labeling of the medicine will now cause patients and physicians alike to approach it with a little more caution.

In a review of the case series presented by Pfizer and the FAERS database, the FDA noted a number of adverse reactions were experienced by patients drinking alcohol while being treated with Chantix.

These adverse reactions were related to a decreased tolerance for alcohol and included increased intoxication, loss of memory and aggressive or uncharacteristic behavior.

Additionally, in their review of the FAERS database, the FDA identified cases of patients being treated by Chantix having seizures who had either no previous history of seizures or a well-controlled seizure disorder. The FDA found that the majority of these cases occurred within the first month of treatment.

The “Warnings and Precautions” section of the medicine’s label will now be updated to include information about these risks, along with additional information obtained from observational studies examining the risk of Chantix affecting patients’ mood and behavior.

Although the observational studies and randomized controlled clinical trial data conducted by Pfizer did not demonstrate an increased risk of neuropsychiatric side effects, they each had limitations that prevented the FDA from coming to any reliable conclusions.

In response to these newfound risks, the FDA recommend that patients being treated with Chantix should reduce the amount of alcohol they consume until they know to what extent the medication affects their capacity to tolerate alcohol.

Before taking Chantix, patients are also advised to inform their health care professional if they have a history of seizures, drink alcohol or have a history of mental health problems.

Patients should be on the look out for changes in behavior or thinking that are uncharacteristic of them, as these could potentially be side effects of the medication. “We urge health care professionals and patients to report side effects involving Chantix to the FDA MedWatch program,” conclude the FDA.

Last month, Medical News Today reported on a study suggesting that several concerns regarding fraudulent clinical trials known to the FDA have not been made public to journals or patients.