Yes, FDA encourages you to report problems with any drug, even if it’s unapproved. Problems include adverse events and product defects. An adverse event is an undesired side effect associated with a drug or a lack of effectiveness—the drug doesn’t do what you expect it to do. Adverse events also include reactions in people who handle the drug. Product defects are problems such as defective packaging or an abnormal appearance of the drug. By reporting adverse events and product defects related to animal drugs, including unapproved ones, you help FDA more easily identify and correct problems.