Some common side effects of Toprol^® (short for Toprol-XL^®) include depression, dizziness, tiredness, and shortness of breath. Uncommon side effects of Toprol can include hepatitis, headache, allergic reactions, and an increase in liver enzymes. There are also a number of Toprol side effects that you should report immediately to your healthcare provider. A few of these side effects include itching, wheezing, and chest pain. You should also let your healthcare provider know if you experience anything that "just does not seem right" while taking Toprol. He or she will be able to diagnose and treat the problem.