Levothyroxine should be used with caution in individuals with certain health conditions due to its potential effects on the body. People with heart disease, especially those with coronary artery disease or a history of heart attacks, should be closely monitored, as an excessive dose can increase the risk of heart palpitations, chest pain, and arrhythmias. Individuals with adrenal insufficiency (such as Addison’s disease) should have their adrenal function addressed before starting levothyroxine, as the treatment can worsen adrenal insufficiency if not properly managed. Elderly patients may require lower starting doses to minimize the risk of cardiac events and other side effects. While levothyroxine is generally considered safe during pregnancy, the dose may need to be adjusted to prevent untreated hypothyroidism, which can harm both the mother and baby. Additionally, levothyroxine can interact with several medications, including antacids, iron, and calcium supplements, which may interfere with its absorption. It is essential to take these supplements several hours apart from levothyroxine to avoid interaction. Regular monitoring of thyroid hormone levels is important to ensure proper dosing and avoid symptoms of hyperthyroidism, such as rapid heartbeat and nervousness.