You may experience some or none of the side effects with Toprol explained in this article. Unfortunately, there is no way for your healthcare provider to know beforehand if you will develop side effects from a medicine that you have never tried. Therefore, make sure to let your healthcare provider know if you develop any side effects, or if anything "just does not seem right," during treatment. While it may not be a side effect, your healthcare provider will be able to diagnose and treat the problem.