The U.S. Food and Drug Administration took action today to halt the distribution and use of nearly 500 unapproved prescription cold or allergy medications, including unapproved medications that are marketed to children. Noting that many approved remedies are available, an FDA official said there simply isn't a reason to meddle with unapproved medications and the risks that they might present.

An FDA release noted that many doctors are unaware that these products are unapproved, in part because they existed prior to more stringent regulatory standards. Companies with products on the list are expected to stop manufacturing them for U.S. sale in 90 days and to stop distribution in 180 days.

Patients taking any of these medications should discuss alternatives with their doctors. Examples of the medications include old sedating antihistamines, which have largely been replaced by non-sedating antihistamines that carry fewer side effects. One advocacy group noted that many of the ingredients in these prescription products are used in FDA-approved medications.

Today's action is but the latest in a five-year-old campaign by the FDA to improve the safety of cough and cold medications. In 2008, the federal agency issued a warning against children two and younger taking over-the-counter cold remedies, because of the risk of severe side effects.