Guaifenesin warning letter

Carolina Pharmaceuticals' guaifenesin- and potassium guaiacolsulfonate-containing products are unapproved new drugs, FDA states in a March 12 warning letter citing Humibid L.A. and Humibid DM (which also contains dextromethorphan). The agency "is unaware of substantial scientific evidence" showing such a combination "is generally recognized by qualified experts as safe and effective," the letter states. The products also are considered new drugs because labeling describes them as offering sustained-release formulations, which must be approved, FDA states. The letter notes the products are reformulated versions of drugs previously marketed under the Humibid brand. The Cary, N.C. firm purchased rights to the brand name at the end of a grace period temporarily allowing continued Rx sale of single-ingredient extended-release guaifenesin products (1"The Tan Sheet" March 3, 2003, p. 4)...