Efficacy and Safety of Treatment With Low Doses of Spironolactone in Patients With Primary Aldosteronism: A Retrospective Observational Study in a Tertiary Center

Background. Spironolactone is recommended as first-line therapy for patients with idiopathic primary aldosteronism. The aim of this study is to evaluate the impact of low and high doses of spironolactone on arterial blood pressure control, potassium levels and on the incidence of drug-related adverse effects. Methods. We retrospectively included 394 patients with primary aldosteronism receiving spironolactone. Patients were divided into two groups, according to the median prescribed dose in our population (50 mg, 25 – 75): subjects treated with doses ≤ 50 mg vs. > 50 mg. Results. The median follow-up after the introduction of spironolactone was 12 months, and 128 patients experienced adverse effects, with a proportion higher in men than in women (44.70% vs. 15.70%). The most frequently reported adverse effect was gynecomastia, followed by sexual dysfunction. Subjects receiving a dose > 50 mg of spironolactone displayed a higher prevalence of adverse effects (39.1%) compared the ≤ 50 mg group (29.3%); this effect was significantly different only in men (p= 0.002). Patients in the low doses group were treated with a higher number of anti-hypertensive drugs, especially diuretics. No significant differences were seen between the two subgroups in blood pressure control, potassium and renin levels and occurrence of cardiovascular events at follow-up. Conclusions. Treatment with low doses of spironolactone, in association with other antihypertensive drugs, is effective in achieving an appropriate blood pressure control in primary aldosteronism, while it improves adherence with lower adverse effects. These findings could help the clinician choose the best therapeutic option for each patient.