Over-the-counterLower-cost generic available

Mucinex Dm

(Dextromethorphan / Guaifenesin)

Over-the-counterLower-cost generic available
  • Pill
  • Extended release
  • Liquid
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Breaks up mucus and relieves cough.

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Our bottom line

Mucinex Dm (Dextromethorphan / Guaifenesin) is okay for loosening congestion in your chest and throat, but it could prevent you from coughing the mucus up. It comes as an extended-release tablet and a short-acting liquid.

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  • Mucinex Dm (Dextromethorphan / Guaifenesin) is a combination medicine that relieves multiple cold symptoms. It's good to use if you have chest congestion and a cough.
  • Helps loosen the mucus and phlegm that builds up in productive and wet coughs.
  • The extended release version of Mucinex DM lasts up to 12 hours.


  • Mucinex Dm (Dextromethorphan / Guaifenesin) isn’t useful if you have a dry cough without mucus or phlegm.
  • The two medications in this product could potentially work against each other. Guaifenesin makes mucus easier to cough up, while dextromethorphan (the "DM" in Mucinex Dm (Dextromethorphan / Guaifenesin)) stops you from coughing.
  • Can cause sleepiness, dizziness, and an upset stomach.
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Side effect rates for Mucinex Dm (Dextromethorphan / Guaifenesin)

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These are side effects of Mucinex Dm (Dextromethorphan / Guaifenesin) reported to the FDA by people taking it, and by doctors and pharmacists.
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Risks and Warnings for Mucinex Dm (Dextromethorphan / Guaifenesin)

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  • People taking Mucinex Dm (Dextromethorphan / Guaifenesin) have reported nausea and vomiting. This is very rare and usually not serious. If you develop a fever with the nausea and vomiting, then talk to your doctor right away.

Common concerns from people taking Mucinex Dm (Dextromethorphan / Guaifenesin)

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  • Last winter I had this problem where when I would lay down to sleep I would start coughing. I took this and 20 minutes later I laid down - no coughing. After a week or so the problem went away. Came back again later and this helped again.
  • I always use this and nasal irrigation to break up mucus. Extremely effective. Best to avoid taking before you are about to do any strenuous or highly social activity - or at least have a lot of tissues on hand.