The inability of the FDA to effectively warn healthcare providers and patients about drug interactions and our inability to translate existing knowledge into changes in prescribing  have resulted in huge economic consequences for the pharmaceutical industry and the loss from the marketplace of effective drugs, including terfenadine, mibefradil, astemizole, and cisapride.

These five drugs were removed from the market or restricted in their use because it became clear that they continued to be prescribed in an unsafe manner, even after multiple warning letters were disseminated by the manufacturer and the FDA to health care professionals concerning their proper use.  Each of these drugs has value in the pharmaceutical marketplace, and each has value to patients.  However, because the manufacturer and the FDA could not prevent co-prescription of these drugs with interacting drugs resulting in fatal interactions, the risk associated with continued widespread availability could not be justified.