Allegra-D contains a combination of fexofenadine and pseudoephedrine. Fexofenadine is an antihistamine that reduces the effects of natural chemical histamine in the body. Allegra-D 24 Hour (fexofenadine hcl 180 and pseudoephendrine hcl 240) is a combination of an antihistamine and a decongestant used to treat sneezing, cough, runny or stuffy nose, itchy or watery eyes, hives, skin rash, itching, and other symptoms of allergies and the common cold. How to use Allegra-D 24 Hour. If you are taking the over-the-counter product to self-treat, read all directions on the product package before taking this medication. ALLEGRA-D® 12 HOUR (fexofenadine hcl and pseudoephedrine hcl) (fexofenadine hydrochloride and pseudoephedrine hydrochloride) Extended-Release Tablets for oral administration contain 60 mg fexofenadine hydrochloride for immediate release and 120 mg pseudoephedrine hydrochloride for extended release Doctors give trusted answers on uses, effects, side-effects, and cautions: Dr. Sinha on can you take allegra and mucinex together: Mcinex liquefies mucous , should not be taken with lot of medicines, zyrtec (cetirizine) would dry up mucous, so donot take togather. WebMD provides a comprehensive overview of drugs used to treat and prevent allergic reactions. Explains the medication fexofenadine (Allegra, Allegra Allergy, Children's Allegra, Allergy 24-HR, Mucinex Allergy), a drug used for the temporary relief of runny nose, sneezing, and nasal stuffiness from the common cold. Allegra-D 24 Hour treats sneezing, cough, runny nose, watery eyes and other symptoms of allergies and the common cold. Includes Allegra-D 24 side effects, interactions and indications. Allegra is the brand name of fexofenadine, an over-the-counter medication used to treat the signs and symptoms of allergies and hives. Allegra is in a class of medications known as antihistamines. Sticking with the Allegra theme… I was taking a rare moment to relax last night (usually I’m running around with my head cut off!), and while I was watching TV (American Idol to be more specific) a Zyrtec commercial came on.