In the United States there are strict controls in place to first approve a drug for the general market or prescription market and secondly to continue monitoring the drug once it has been approved. However, even with such controls, sometimes drugs can cause previously unanticipated side effects in patients or in most serious cases, death. Such drugs are called defective drugs and persons who have been medicated with such drugs in many cases do have valid claims to the makers of the drug for medical treatment or monetary compensation.

Before a drug can be sold in the United States it is put through a series of trials and must gain the approval of the Food and Drug Administration (FDA). The FDA approval is seen as one of the most stringent in the world and many countries will simply approve a drug once the FDA has approved it, without the requirement of further trials. Once the drug has the approval to be prescribed, the FDA continues to monitor it through post-marketing reports sent in by the manufacturer and through the MedWatch program. The MedWatch program is an FDA-sponsored program that allows consumers and doctors to report serious side effects, quality control issues, and medical errors associated with drugs and products regulated by the FDA.

In some cases, an unanticipated side effect may manifest itself once the drug has been prescribed to patients. For mild unanticipated side affects, the FDA may simply require the maker of the drug to change the labeling; however, if the side effect is serious enough, the FDA may issue a warning to the public or in extreme cases recall the drug. If a drug that you have been taking has been recalled, immediately contact your physician.