Critical
losartan × spironolactone
Angiotensin II receptor blockers (sartans)×Potassium-sparing diuretics (mineralocorticoid receptor antagonists)
Mechanism
Same as the ACE-inhibitor/spironolactone pair: the ARB blocks AT1 receptors and lowers aldosterone synthesis, while spironolactone blocks the mineralocorticoid receptor. Dual potassium-sparing action causes hyperkalemia, especially in older patients with CKD or diabetes.
Management
Justified in HFrEF (ESC 2024 guidelines). Start spironolactone at 12.5–25 mg. Monitor potassium and creatinine on the same schedule as for ACE inhibitors. If K+ exceeds 5.5 mmol/L, reduce the dose or discontinue.
Sources
- EMPHASIS-HF Investigators: Eplerenone in Patients with Systolic Heart Failure and Mild Symptoms (2011)— N Engl J Med 2011;364(1):11–21
- ESC: 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure (2021)— Eur Heart J 2021;42(36):3599–3726
- ESC: 2023 Focused Update of the 2021 ESC Guidelines for the treatment of heart failure (2023)— Eur Heart J 2023;44(37):3627–3639