Starting levothyroxine in older adults requires caution due to potential risk of which complication?

• A. Gastrointestinal upset
• B. Hypotension
• C. Cardiovascular complications
• D. Weight gain

Answer: (C)

Initiating thyroid hormone replacement in older adults must be approached with caution because the heart can react strongly to thyroid hormone. Levothyroxine increases overall metabolic demand, heart rate, myocardial contractility, and oxygen use. In elderly patients, especially those with underlying coronary artery disease or limited cardiovascular reserve, this can precipitate cardiovascular events such as angina, arrhythmias (like atrial fibrillation), myocardial ischemia, or even heart failure. That’s why the primary concern is cardiovascular complications, and dosing is started very low with slow titration and close monitoring of heart rate, blood pressure, symptoms (chest pain, palpitations, dyspnea), and thyroid function tests.

Gastrointestinal upset, while possible with many medications, is not the main risk when starting levothyroxine. Hypotension isn’t the typical immediate issue; the concern is not a drop in blood pressure but rather overstimulation of the heart leading to tachyarrhythmias or ischemia. Weight changes are more a reflection of thyroid status over time and are not the acute complication clinicians worry about at initiation.