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.
Mucinex DM relieves coughing caused by the common cold, bronchitis and allergies. It contains the expectorant guaifenesin, which loosens mucus in the lungs and airways, allowing coughs to be productive. It also contains dextromethorphan, which affects the brain by suppressing the urge to cough.