The FDA has notified healthcare professionals and patients that it has required manufacturers of varenicline (Chantix, from Pfizer) and bupropion (Wellbutrin, Wellbutrin SR, Wellbutrin XL, and Zyban, from GlaxoSmithKline) to add new Boxed Warnings to the product labeling and develop patient Medication Guides highlighting the risk of serious neuropsychiatric symptoms.