Phenylephrine is a medication used as a decongestant to relieve nasal and sinus congestion caused by seasonal allergies, hay fever, and the common cold. Synonyms for phenylephrine include Neo-Synephrine, Sudafed PE, Vazculep, and Phenylephrine HCl. Neo-Synephrine is a nasal spray that contains phenylephrine hydrochloride used to reduce swelling of the nasal passages and is often used as a substitute for pseudoephedrine in over-the-counter cold and allergy medications. Sudafed PE is a brand name for phenylephrine hydrochloride tablets and is also used to relieve nasal and sinus congestion. Vazculep is a brand name for phenylephrine hydrochloride injection and is used to increase blood pressure in certain medical situations.