The following are some of the less common symptoms that you may experience after taking tramadol: nausea, bloating, blood in the urine, chills, increased blood pressure, abdominal or stomach pain, difficulty urinating, fainting, heart rate increased, and loss of memory. It needs to be noted that these symptoms can also be caused by other health issues, so if you only experience one of these symptoms, do not panic, but do consult your doctor to get further information.