Patients may be asking health care providers about the safety and effectiveness of Mucinex (Adams), which is being heavily advertised on television and elsewhere for treatment of respiratory congestion. These ads suggest that Mucinex is a new drug, when actually it is an extended-release formulation of guaifenesin, an old expectorant. Guaifenesin increases the volume of secretions in the respiratory tract, which facilitates removal of viscous mucus by coughing. Medical Letter consultants have not been impressed by its effectiveness. Guaifenesin is in the category of drugs - Generally Recognized as Safe - (GRAS) and is included in many prescription and over-the-counter cough remedies,1 but the manufacturer of Mucinex nevertheless sought and received FDA approval. Now the FDA has removed all single-ingredient extended-release guaifenesin products from the market until the manufacturers also apply for and receive approval. Mucinex is available without a prescription for patients 12 years or older and is taken every 12 hours. A bottle of 20 600-mg tablets costs about $12 at a local chain pharmacy.

1. Over-the-counter (OTC) cough remedies. Med Lett Drugs Ther 2001; 43:23.