Sudafed PE contains the nasal decongestant phenylephrine, while the other formulations don't. Since phenylephrine can be used for the illegal production of methamphetamine in large quantities, you have to sign.
Regular Sudafed contains pseudoephedrine, a substance that is one of the main ingredients in meth. Sudafed PE contains phenylephrine. Pseudoephedrine recently became a controlled substance.
