Background: Loop-diuretics are used for congestion relief and dose-adaptations are usually a consequence of the clinicians` clinical judgement about the congestive status of the patient. In EPHESUS (Eplerenone in Patients with Systolic Dysfunction after Myocardial Infarction) many of the patients had heart failure (HF) requiring diuretics for congestion relief. We thus hypothesized that blinded allocation to eplerenone would lead clinicians to reduce loop diuretics, as consequence of the improvement in patients` status. Aims: To study the effect of eplerenone on the diuretic doses during the follow-up, and its prognostic implications. Methods: Cox and mixed effect models were used over a median follow-up of 1.3 years in 6632 patients. Results: A total of 6632 patients were included; at baseline 3352 (50.5%) did not have diuretics, 2195 (33.1%) had diuretic doses between 1 and 40 mg/day, and 1085 (16.4%) had diuretic doses above 40 mg/day. Patients with higher furosemide equivalent doses had a worse clinical status. Both baseline and follow-up incremental loop diuretic doses were associated with worse prognosis. Eplerenone treatment was associated with lower prescribed loop diuretic doses throughout the follow-up; lower doses were observed at 90 days, and decreased further at 180 days and beyond. Eplerenone treatment led to a mean furosemide equivalent dose reduction of -2.2 mg/day (-2.9 to -1.6) throughout the follow-up. Eplerenone was effective in reducing morbidity and mortality regardless of the baseline loop diuretic dose used: HR (95%CI) for the outcome of cardiovascular death or HF hospitalization =0.83 (0.75-0.92); p for interaction =0.54. Conclusion: Eplerenone treatment led to a loop diuretic dose reduction during follow-up without evidence of treatment effect modification by loop diuretics. These findings suggest that eplerenone reduces congestive signs and symptoms, which enables clinicians to reduce loop diuretic doses.