This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
A 72-year-old man is prescribed hydrochlorothiazide for hypertension. Which of the following is the most likely symptomatic side effect? 
Select and explain. 
A. increased serum potassium, B. metabolic acidosis, C. sexual impotence, D. respiratory alkalosis
C: sexual impotence
Answer: C: sexual impotence 
Explanation: The most common symptomatic side effect in men is impotence, and it should be specifically looked for. The most serious complications relate to fluid and electrolyte imbalance and include hyponatremia, hypokalemia, and volume contraction.