History. Phenylephrine and Pseudoephedrine
Phenylephrine and pseudoephedrine are both decongestants. Historically, pseudoephedrine has been the more commonly used decongestant in many nonprescription cold and allergy medications. However, pseudoephedrine is also a key ingredient in making methamphetamine, a highly addictive illegal stimulant. Federal law now requires all nonprescription medications containing pseudoephedrine to be unavailable over the counter and kept behind the counter in the pharmacy. To purchase pseudoephedrine, one must show some form of government-issued identification and sign a logbook. Most products have been or are being reformulated with phenylephrine.