Washington, D.C. ? Manufacturers of unapproved extended-release cough and cold drugs that contain an expectorant called guaifenesin have until Nov. 25 to stop shipping the medicines, health officials said Friday.

The Food and Drug Administration said roughly 20 companies make hundreds of timed-release medicines containing guaifenesin that have never undergone agency review. They are expected to stop making the drugs even earlier, by Aug. 27.

Friday’s action does not affect products containing guaifenesin in immediate-release form, the FDA said. The agency said it knew of no safety issues with guaifenesin, which has been used in medicines for decades. The drug stimulates removal of mucous from the lungs.

Only one company, Adams Respiratory Therapeutics Inc., currently has FDA approval to sell extended-release guaifenesin. In 2002, the FDA approved single-ingredient versions of the medicines, sold as Mucinex and Humibid.

The FDA identified Crantex and Guaifenex as among the biggest selling names of unapproved, immediate-release guaifenesin medicines.