MEDizzy - A patient taking an oral diuretic for about 6 months

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The Renal System and Diuretics Pharmacology

A patient taking an oral diuretic for about 6 months presents with elevated fasting and postprandial blood glucose levels. You check the patient’s HbA1c and find it is elevated compared with normal baseline values obtained 6 months ago. You suspect the glycemic problems are diuretic-induced. Which of the following was the most likely cause?

ExplanationThi- azides and thiazide-like diuretics (e.g., chlorthalidone, metolazone) may elevate blood glucose levels, impaired glucose tolerance, and cause frank hyperglycemia. The loop diuretics may do the same. Several mechanisms have been proposed to explain the effect: decreased release of insulin from the pancreas; increased glycogenolysis and decreased glucogenesis; a reduction in the conversion of proinsulin to insulin; and reduced responsiveness of adipocyte and skeletal myocyte insulin receptor response to the hormone. (You might recall that diazoxide [mainly used as a parenteral drug for prompt lowering of blood pressure] can be used in its oral dosage form to raise blood glucose levels in some hypoglycemic states. It is, chemically, a thiazide, but is not used as a diuretic.)