Robitussin produces a wide range of products with different formulations. These formulations each contain a different combination of ingredients designed to address different symptom profiles, mostly concentrating on relieving cough with or without congestion. All formulations of Robitussin contain at least one of five common active ingredients, although most contain a combination of two or more ingredients.
Dextromethorphan HBr
Dextromethorphan is a cough suppressant. It prevents coughing by dampening activity in the part of the brain that controls coughing. Dextromethorphan used alone is best used to relieve a dry, unproductive cough, particularly if the cough is interfering with daytime activities or preventing restful sleep.
Guaifenesin
Guaifenesin is a member of a class of drugs called expectorants, which thin mucous secretions in the airways. Guaifenesin is best used to help a productive cough become more productive and helps relieve coughing over time by helping the body clear the irritating mucous from the airways. It is sometimes paired with dextromethorphan in order to control the cough while making the coughing that continues to occur more productive.
Chlorpheniramine Maleate and Diphenydramine
Chlorpheniramine maleate and diphenydramine are antihistamines used to reduce sneezing, itchy or watery eyes and runny nose. Antihistamines work by decreasing the action of histamine, a substance in the body that causes edema and swelling in mucous membranes. These two ingredients are included separately in different formulations and are sometimes paired with phenylephrine.
Phenylephrine HCl
Phenylephrine is a nasal decongestant. Nasal decongestants restore freer breathing by reducing the swelling of nasal and sinus tissues. It is sometimes combined with an antihistamine. It is not a good idea to take preparations that contain decongestants and antihistamines when the primary symptom is coughing because these medications tend to dry out mucous membranes and can make a productive cough less productive.
