Phenylpropanolamine is the N-desmethylanalog of ephedrine and thus has many similar properties.Lacking the N-methyl group, phenylpropanolamine is slightlymore polar, and therefore does not enter the CNS as well asephedrine. This modification gives an agent that has slightlyhigher vasopressive action and lower central stimulatoryaction than ephedrine. Its action as a nasal decongestant ismore prolonged than that of ephedrine. It is orally active.Phenylpropanolamine was a common active component inOTC appetite suppressants and cough and cold medicationsuntil 2001 when the Food and Drug Administration (FDA)recommended its removal from such medications, becausestudies showed an increased risk of hemorrhagic stroke inyoung women who took the drug.
