 <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]  side effects. Many people using this medication do not have serious side effects. Though unlikely, it is possible to have too much thyroid hormone. Tell your doctor right away if you have symptoms of too much thyroid hormone, including: headache, mental/mood changes (such as irritability, nervousness), increased sweating, sensitivity to heat, diarrhea, menstrual changes. Get medical help right away if you have any very serious symptoms of too much thyroid hormone, including: chest pain, fast/pounding/irregular heartbeat, swelling ankles/feet, trouble breathing, unusual tiredness. 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 </s>