Key takeaways
Mucinex D (guaifenesin/pseudoephedrine) and Mucinex DM (guaifenesin/dextromethorphan) are both over-the-counter medications used to relieve cold symptoms, but they have different active ingredients and uses. Mucinex D combines guaifenesin, an expectorant that loosens mucus, with pseudoephedrine, a decongestant that relieves nasal and sinus congestion. It is taken every 12 hours and can cause side effects like trouble sleeping and headache. On the other hand, Mucinex DM combines guaifenesin with dextromethorphan, a cough suppressant that reduces the urge to cough. Mucinex DM is available in various forms, including tablets, liquids, and granules, and can be taken every 4 to 12 hours depending on the formulation. It may cause drowsiness and dizziness. While both medications help with chest congestion, Mucinex D is better for nasal congestion, and Mucinex DM is better for suppressing coughs.
