Hello:
The side effects of this medication are pretty rare. Tramadol can decrease heart rate in some dogs, if given shots. It is also only registered for human use only, but is used in veterinary medicine. :) You can read all about this medication at the site below:
http://www.petplace.com/drug-library/tramadol-hydrochloride-ultram/page1.aspx
Good luck with your baby :)
breeder/healthcare specialist
15+ years animal health care Hobby breeder of Olde English Mastiffs and owned by an English Bulldog