The Food and Drug Administration (FDA) has announced that the labeling for varenicline (Chantix; Pfizer) has been updated to include information on changes to alcohol tolerance and risk of seizures associated with use of the drug. Varenicline is approved as a smoking cessation aid in adults over the age of 18.

The updated Warning and Precautions section of the label is based on a case series submitted by Pfizer and cases in the FDA Adverse Event Reporting System (FAERS) database, which describe patients who consumed alcohol during varenicline treatment and experienced adverse reactions including decreased tolerance to alcohol, unusual or aggressive behavior, or no memory of past events. A review of FAERS and the medical literature also identified cases of seizures with varenicline treatment in patients with no history of seizures or a seizure disorder that had been well-controlled. These seizures occurred within the first month of varenicline therapy in most cases.

The labeling will also include information on several studies investigating the risk of neuropsychiatric side effects on mood, behavior, or thinking occurring with varenicline. While these studies did not show an increased risk of neuropsychiatric side effects with varenicline, they did not examine all types of neuropsychiatric side effects and had limitations that prevented the FDA from drawing reliable conclusions. Pfizer is currently conducting a large clinical safety trial to investigate the risk and the study results are expected in late 2015.

RELATED: Varenicline May Help Smokers Not Yet Ready to Quit

Recommendations for healthcare professionals include:

  • Advising patients to reduce the amount of alcohol they consume while taking varenicline until they know whether the drug affects their tolerance for alcohol
  • Weighing the potential risk of seizures against the potential benefits before prescribing varenicline in patients with a history of seizures or other factors that can lower the seizure threshold
  • Advising patients to discontinue varenicline and seek medical attention immediately if they experience a seizure while on treatment
  • Advising patients to immediately stop taking varenicline if they develop agitation, hostility, aggressive behavior, depressed mood, or changes in behavior or thinking that are not typical for them, or if they develop suicidal ideation or behavior
  • Encouraging patients to read the patient Medication Guide they receive with their varenicline prescription
  • Reporting adverse events involving varenicline to the FDA MedWatch program

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