Common side effects include nausea, vomiting, headache, loss of appetite, diarrhea, weakness, mental/mood changes, vision changes (such as blurred or yellow/green vision, enlarged or tender breasts in men. Although generic Cardoxin is used to treat a particular type of irregular heartbeat, it may seldom cause other types of irregular heartbeats. Inform your local doctor promptly if you perceive any unusually fast, slow or abnormal heartbeat.