Pharmacology and safety of phenylpropanolamine

Phenylpropanolamine (PPA) is a phenylethylamine found commonly in cough medicines, nasal decongestants, and over‐the‐counter (OTC) diet aids. Since its discovery more than 70 years ago, the pharmacology of this drug has periodically been reexamined as the result of advances in the understanding of the sympathetic nervous system and adrenergic receptor function. This review presents a brief overview of the pharmacology of PPA, with an emphasis on how the drug effects smooth muscle tissues. Additionally, since the safety of PPA has recently been called into question, research pertaining to its toxicity is also reviewed.