Diuretics for Hypertension

A 67-year-old African-American woman was referred to a hypertension specialty clinic for refractory hypertension and intermittent hypokalemia. Evaluations for primary aldosteronism and renal artery stenosis were negative; plasma renin was low. She had been hypertensive for 15 years. Most recently, she had taken chlorthalidone 25 mg, amlodipine 5 mg, and metoprolol 50 mg twice daily. She was not diabetic and had never smoked. Her blood pressures were in the range of 160 to 170/95 to 100 mm Hg. Except for her being mildly overweight (body mass index, 28), the physical examination was unremarkable, with no sign of target organ damage. Voltage criteria for left ventricular enlargement were present on the ECG. She was considered to be adherent to medication. Spironolactone 50 mg/d was prescribed, and her dose of chlorthalidone was reduced to 12.5 mg/d. Over the next year, her blood pressure fell to the range of 135 to 145/85 mm Hg, and serum potassium was consistently normal.This patient was taking three antihypertensive drugs, including a diuretic, which is considered by many as a necessary component for her management, yet remained uncontrolled, with an especially high risk of stroke. The addition of another diuretic was successful in bringing her pressure into an acceptable range and reversed the tendency toward hypokalemia that was caused by the thiazide-type diuretic. What is the lesson here? First, diuretic combinations from different subclasses play an important role in the management of hypertension. Second, salt-sensitive refractory hypertension in the African-American population, reflected clinically by low renin levels, can provide a clue to optimal management.1,2Treatment of hypertension that uses a diuretic-based strategy has been effective in preventing stroke and cardiac disease in the earliest randomized clinical trials in the 1960s, with a consistently successful “track record” extending to contemporary trials, as emphasized …