Which of the following is listed as a side effect of thiazide diuretics?

• A. Hypoglycemia
• B. Hyperglycemia
• C. Hyponatremia
• D. Hypercalcemia

Answer: (B)

Thiazide diuretics commonly cause metabolic changes that include hyperglycemia. The reason is linked to potassium loss in the distal tubule: thiazides cause hypokalemia, and lower potassium levels can impair insulin secretion from pancreatic beta cells, leading to reduced insulin release and higher blood glucose. This glucose intolerance tendency is particularly notable in patients who already have or are at risk for diabetes.

Other options are less characteristic. Hypoglycemia isn’t a typical effect of these diuretics. Hyponatremia can occur with thiazides, but the glucose-related metabolic impact is a well-recognized, documented effect, especially in the context of glucose tolerance. Mild hypercalcemia can occur because thiazides promote calcium reabsorption, but it’s not as consistently emphasized as hyperglycemia in standard side-effect lists.