The U.S. Food and Drug Administration is looking into reports that the anti-smoking drug Chantix may trigger mood swings and thoughts of suicide in patients taking it.

Information provided to the agency by Chantix manufacturer, Pfizer Inc. cited "erratic behavior" in an individual who had used Chantix. The agency is also investigating the death of the person who used the drug, but was also under the influence of alcohol.

The FDA has asked Pfizer for any additional information it has on reports of adverse reactions in people taking the drug. Its Center for Drug Evaluation and Research is analyzing the data and plans to release its findings to the public once the analysis is completed.

In the meantime, the agency recommends that health care providers monitor patients taking Chantix. Patients taking Chantix should contact their doctors if they experience behavior or mood changes, the FDA said.

The FDA also advises that patients taking Chantix use caution when driving or operating machinery due to reports of drowsiness.