*This statement summarizes the third USPSTF recommendations for screening for chlamydial infection and the supporting scientific evidence, and it updates the 1995 recommendations contained in the Guide to Clinical Preventive Services, second edition (1).
Older adults may be more sensitive to the side effects of this drug, especially fast/pounding/irregular heartbeat. Current information shows that this drug may be used during pregnancy. Tell your doctor if you are pregnant because your dose may need to be adjusted. Levothyroxine passes into breast milk but is unlikely to harm a nursing infant.
Over-treatment with levothyroxine may cause increase in heart rate, cardiac wall thickness, and cardiac contractility; may precipitate angina or arrhythmias, particularly in patients with cardiovascular disease and in elderly patients; monitor patients receiving concomitant levothyroxine and sympathomimetic agents for signs and symptoms of coronary insufficiency; initiate lower dose in elderly, those with angina pectoris, cardiovascular disease, or in those with severe hypothyroidism