Duraphen is a combination drug, containing Guaifenesin (an expectorant), which helps loosen chest congestion, making coughs more productive, and Phenylephrine (a decongestant), that shrinks blood vessels in the nose, improving symptoms of nasal congestion. This combination of drugs is used primarily to treat allergic rhinitis, and chest congestion caused by allergies, the common cold or flu.
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Duraphen Wikipedia(Text) CC BY-SA