 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: weakness, mental/mood changes, vision changes (such as blurred or yellow/green vision), enlarged/tender breasts in men. Though this medication is used to treat a certain type of irregular heartbeat, it may rarely cause other types of irregular heartbeats. Tell your doctor right away if you notice any unusually fast/slow/irregular heartbeat. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345. </s>