Pseudophedrine is an alkaloid synthesized from ephedrine. The only physical difference between ephedrine and pseudoephedrine is their structure.
Pseudoephedrine, when converted into pseudoephedrine hydrochloride, is principally used to dilate the bronchioles, and as a nasal decongestant.
Osol, Arthur. 1980. Remington's Pharmaceutical Sciences. Mack Publishing Company, Pennsylvania. 1928 pp.