Pseudoephedrine, can be addictive, it's an ingrediant that has been used in making illegal methamphetimines in the US and has been taken off the market and replaced with a substitute.
It has many effects similar to amphtemine, which has made if popular but sadly, addictive for many.
It's ashame it has gotten to this point because of the "meth labs", many, including myself, found the decongestant OTC meds with this ingrediant seemed to be the most effective sinus aid and didn't make one drowsy like other OTC meds can do. It's always good to clear things with your pdoc or doc before taking OTC meds, some can react with your prescription meds and/or existing physical conditions.
Take care,
DE