THE EFFECT OF SPIRONOLACTONE VERSUS TORSEMIDE ON BLOOD PRESSURE TARGETS IN RESISTANT HYPERTENSION PATIENTS

Abstract

Objective: to evaluate effects on blood pressure (BP) control in two treatment options spironolactone (SPIR) versus torsemide (TOR) as an add-on therapy in resistant hypertensive (RAH) patients. Design and method: We studied 78 patients with true RAH confirmed by the office and ambulatory BP monitoring (ABPM). Patients were randomized into 2 groups through 12 weeks of once daily treatment with of SPIR (25–50 mg) or TOR (5–10 mg) in addition to their baseline triple-combination and then rotated with drugs. BP was measured in the office and by ABPM. Changes in laboratory tests were also studied. The predictive values of plasma aldosterone, active renin concentration (ARC) and aldosterone-renin ratio (ARR), serum potassium, 24-h urinary excretion sodium of determining the antihypertensive response were analyzed. Results: There were no significant differences on the reduction of average office BP and average nighttime BP by SPIR and TOR. SPIR reduced average systolic 24-h BP by 11.7 mmHg and average systolic daytime BP by 12.2 mmHg compared with a reduction of 8.9 mmHg (P < 0.05) and 9.1 mmHg (P < 0.05) with TOR, respectively. Overall, 36.8 % RAH patients achieved targets of clinical BP and 24-h ABPM levels on SPIR and 30.9 % on TOR. After 12 weeks of treatment mean plasma potassium concentrations increased from 4.3 to 4.7 mmol/L (P < 0.0001) on SPIR but did not significant change on TOR. Serum potassium (β = −0.441, P < 0.05), 24-h urinary excretion sodium (β = 0.432, P < 0.05) and ARR (β = 0.543, P < 0.03) were predictors of BP-lowering effect of SPIR and plasma aldosterone (β = −0.680, P < 0.001), ARC (β = 0.463, P < 0.03) were predictors of reduction BP for TOR in multivariate modeling. Conclusions: Greater antihypertensive effect of SPIR is related to aldosterone status, urinary sodium excretion and serum potassium level in resistant hypertension. TOR may be suited for RAH patients that have high ARC and in people with lower sodium intake or high serum potassium level.