What Is the Difference Between Sudafed and Sudafed PE?

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According to Sudafed.com, Sudafed uses pseudoephedrine as a nasal decongestant, while Sudafed PE uses phenylephrine or PE. Because pseudoephedrine is used illegally to make meth, the original Sudafed formula is federally regulated and can only be purchased at a pharmacy or service counter while Sudafed PE can be purchased without such restrictions and is usually found on the cold and allergy aisle.