Tramadol is a popular opioid painkiller that is often considered safer. Extensive analysis of clinical trials has found that it relieves chronic pain, but the relief is only mild. This relief is so small that many patients would probably not experience much benefit in real life. At the same time, tramadol is associated with a significantly higher risk of serious side effects. These include heart problems such as chest pain and heart failure in particular. Common side effects include nausea, dizziness and drowsiness.