Major
Losartan × Spironolactone
Angiotensin II receptor blockers (sartans)×Potassium-sparing diuretics (mineralocorticoid receptor antagonists)
Mechanism
Losartan (angiotensin II receptor blocker, ARB) suppresses the renin-angiotensin-aldosterone system and reduces aldosterone release. Spironolactone directly blocks aldosterone receptors. Both retain potassium.
Symptoms
Muscle weakness, paraesthesia in the limbs, slowed pulse, arrhythmias. ECG shows peaked T waves and widened QRS. Severe cases progress to cardiac arrest. Symptoms typically appear within 1–2 weeks of starting the combination.
Management
The combination is appropriate in heart failure. Check potassium and creatinine 1 week after start, then monthly. If potassium exceeds 5.5 mmol/L, reduce the dose of one agent; above 6.0 mmol/L, stop one of them.
Sources
- 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
- EMPHASIS-HF Investigators: Eplerenone in Patients with Systolic Heart Failure and Mild Symptoms (2011)– N Engl J Med 2011;364(1):11–21