Key takeaways
Acetaminophen/dextromethorphan/phenylephrine (Dayquil) and guaifenesin/pseudoephedrine (Mucinex D) are both over-the-counter medications used to relieve symptoms of the common cold, such as nasal congestion. However, they belong to different medication classes and have distinct uses. Dayquil is a combination of an analgesic, a cough suppressant, and a decongestant and is used for short-term relief of cold and flu symptoms like minor aches, cough, and fever. On the other hand, Mucinex D combines an expectorant and a decongestant to relieve chest congestion and sinus pressure. Dayquil is typically taken every 4 hours, while Mucinex D comes as an extended-release tablet taken every 12 hours. Both medications are available as generics, but Mucinex D is behind-the-counter in some states due to pseudoephedrine. Common side effects of Dayquil include stomach upset and nervousness, while Mucinex D can cause trouble sleeping and headaches. Both medications should not be taken with monoamine oxidase inhibitors (MAOIs) and can interact with other medications, so talk to your prescriber or pharmacist before using either one.
