Spironolactone therapy in older patients—the impact of renal dysfunction

Low dose spironolactone reduces the risk of death from heart failure. We examined the effects of spironolactone on potassium homeostasis in a cohort of elderly patients with congestive heart failure (CHF). Eighteen patients >70 years, mean 80.5 (±SD 6.3) with New York Heart Association CHF Grade II–IV were enrolled. All patients were commenced on 25 mg spironolactone daily. The dose was reduced to 12.5 mg daily when hyperkalemia (potassium >5.0) occurred. A serum creatinine of >150 μmol/l was defined as indicating renal impairment (RI). Blood pressure, pulse rate, urea, creatinine, Na + and K + were measured at baseline, day 2–5, day 28 and more often if clinically indicated. Nine of those recruited had RI. Baseline serum potassium was significantly higher in those with RI, mean 4.56 (±0.30) vs. 4.04 (±0.30) mmol/l ( P