Phenylephrine or Neo-Synephrine is an α1-adrenergic receptor agonist used primarily as a decongestant, as an agent to dilate the pupil, and to increase blood pressure. Phenylephrine has recently been marketed as a substitute for pseudoephedrine (for example, Pfizer's Sudafed (Original Formulation)), but there are recent claims that oral phenylephrine may be no more effective as a decongestant than a placebo. Uses Decongestant Phenylephrine is used as a decongestant sold as an oral medicine… (More on Phenylephrine)