Key takeaways
Mucinex DM (guaifenesin/dextromethorphan) and Guaifenesin AC (codeine/guaifenesin) are both used to relieve cough and loosen mucus, but they have some key differences. Mucinex DM is an over-the-counter medication that combines an expectorant (guaifenesin) and a cough suppressant (dextromethorphan). It is available in various forms like tablets, liquids, and granules, and can be taken by people as young as 4 years old, depending on the formulation. On the other hand, Guaifenesin AC is a prescription-only medication that combines an expectorant (guaifenesin) with an opioid (codeine). It is a controlled substance due to the potential for addiction and misuse, and it is not recommended for children under 12 years old. While Mucinex DM can cause mild side effects like dizziness and drowsiness, Guaifenesin AC has more serious risks, including the potential for dangerously slow breathing and life-threatening interactions with other medications. Additionally, Guaifenesin AC is meant for short-term use only because of the risk of dependence.
