Sudafed® (pseudoephedrine hydrochloride) is a medication used for relieving nasal and sinus congestion due to allergies or the common cold. There are several different forms of Sudafed: tablets (immediate-release and extended-release) and liquid.
Sudafed is part of a class of drugs called decongestants. Specifically, it works by stimulating certain receptors known as alpha-adrenergic receptors. In the lining of the nose and sinuses, this action causes the blood vessels to constrict, allowing less fluid to leave the blood vessels and decreasing inflammation. This helps to relieve nasal and sinus congestion.
Although you do not need a prescription to buy the liquid or tablet form of Sudafed in most states, you do need to show identification to buy such products (any medication containing pseudoephedrine is required to be kept behind the pharmacy counter). You will also be limited to a certain amount of the medication per month. These measures were put in place to decrease the use of pseudoephedrine to make methamphetamine.
(Click Sudafed to learn more about the effects of this medication, for a list of the various strengths available for the liquid and tablet versions of Sudafed, and to find out what side effects may occur with the medicine.)