Think before you prescribe - Monitor electrolytes in hypertensive patients on thiazide diuretics

Think before you prescribe

Monitor electrolytes in hypertensive patients on thiazide diuretics

Thiazide diuretics have been widely used for the treatment of hypertension. Their efficacy and cost-effectiveness often makes them a first-line choice in treating hypertensive patients. However, their effectiveness in patients with chronic kidney disease (CKD), especially those with a glomerular filtration rate less than 30 ml/min/1.73 m2, has been of concern. Consequently, they were thought to be ineffective in patients with advanced CKD.

There have been studies, which have documented the beneficial effects of thiazide diuretics in moderate to advanced CKD challenging this widely held belief. Chlorthalidone was found to significantly reduce BP among people with moderate to advanced CKD with poorly controlled hypertension in a small study. Albuminuria was significantly reduced by 40-45% (Am J Nephrol. 2014;39(2):171-82). But, the 2017 ACC/AHA guideline for treatment of hypertension recommend loop diuretics in patients with moderate to severe CKD.

Thiazide diuretics are a common cause of hyponatremia. When prescribed to elderly patients who are also taking drugs e.g. selective serotonin reuptake inhibitors, the resulting hyponatremia can be more severe. Hence, electrolytes should be monitored in these patients.