The FDA's Web site on unapproved drugs is available at www.fda.gov/cder/drug/unapproved_drugs/default.htm
With one exception, timed-release drug products available in the United States that contain the expectorant guaifenesin have not been approved by the Food and Drug Administration and should be taken off the market, according to an agency announcement.
About 20 companies manufacture these products, most of which are available only by prescription. The products include Guaifenex (manufactured by Ethex Corp.), Crantex and Guaifen (Breckenridge Pharmaceutical Inc.), Amibid and Amitex (Actavis Group), Duraphen (Proethic Pharmaceuticals Inc.), Wellbid (Prasco), Ambi (Ambi Pharmaceuticals Inc.), and Maxifed (MCR American Pharmaceuticals Inc.). Many of the products include other active ingredients, the FDA announcement noted.
The FDA ordered manufacturers of these unapproved products to stop making them by Aug. 27 and to cease interstate shipment by Nov. 25, although some inventory will remain in pharmacies after that time.
The action does not affect immediate-release formulations of guaifenesin, only timed-release formulations, which are also described as extended release, long acting, or sustained release.
The only timed-release products containing guaifenesin that have been formally approved by the FDA are those marketed over the counter as Mucinex or Humibid, by Adams Respiratory Therapeutics. Besides Mucinex and Humibid, which contain only guaifenesin, the company makes Mucinex-D, which also contains pseudoephedrine, and Mucinex-DM, which also contains dextromethorphan.
Timed-release products need to be approved because the FDA needs to ensure that “the product releases its active ingredients safely and effectively, sustaining the intended effect over the entire time in which the product is intended to work,” according to the FDA statement.
Dose dumping is a major concern with these products, said Deborah M. Autor, an attorney and director of the office of compliance in the FDA's Center for Drug Evaluation and Research (CDER), during a telebriefing.
The FDA did not look into whether there were any reports of adverse events linked to the unapproved guaifenesin products; adverse event reports did not spur this action, Ms. Autor said.