Safety of spironolactone use in ambulatory heart failure patients

Since the Randomized Aldactone Evaluation Study (RALES), the use of spironolactone is recommended in systolic heart failure (HF) patients that have been in New York Heart Association (NYHA) class III or IV. There is limited information on the use, side effects, and withdrawal rate of spironolactone in routine clinical practice.

Side effects related to spironolactone use are more common than reported in clinical trials.

Patients who had moderate to severe left ventricular systolic dysfunction (LVSD) under optimized medical therapy were included. We introduced spironolactone in those with serum potassium (K+) < or = 5 meq/L, and serum creatinine (Cr) < or = 2.5 mg/dL. Spironolactone was withdrawn if serum K + > or = 5.5 meq/L, serum Cr increased more than 30%- 50% of the baseline value, and/or if the patient had gynecomastia.

We selected 134 patients followed in an HF clinic. In our sample, 56.7% of the patients (76 out of 134) were currently or had formerly been on spironolactone therapy. The rate of spironolactone withdrawal was 25% (19 out of 76). Reasons for suspension were hyperkalemia (17.1%), renal function deterioration (14.5%), gynecomastia (5.3% of males), and other reasons (1.3%).

Spironolactone side effects are common and are mostly related to effects on the angiotensin-aldosterone axis. Our results reinforce the need to closely monitor serum K+ and Cr levels in patients treated with spironolactone, as its side effects are more common than reported in clinical trials.