Codeine (codeine phosphate) contains the active ingredient codeine and is used to reduce pain from headache, the flu and common cold. See here for more information and to order.
A: Mucinex contains the active ingredient guaifenesin, which is an expectorant that helps loosen phlegm and thin bronchial secretions. Mucinex does not have rapid heart rate as a possible side effect. There is a product called Mucinex-D that contains pseudoephedrine, and this ingredient can increase heart rate.
5 Reviews. Mucinex DM is a cough medicine that contains dextromethorphan, a cough suppressant, and guaifenesin, an expectorant that helps loosen mucus in your throat and lungs. This combination of two drugs helps to loosen mucus or phlegm and thin out bronchial secretions, making coughs more productive.