Major
Spironolactone × telmisartan
Potassium-sparing diuretics (mineralocorticoid receptor antagonists)×Angiotensin II receptor blocker (ARB)
Mechanism
Additive hyperkalaemia. Both drugs retain potassium: spironolactone directly blocks aldosterone receptors; telmisartan (ARB) reduces aldosterone synthesis.
Symptoms
Muscle weakness, paraesthesia, slowed pulse, arrhythmias. ECG: peaked T waves, widened QRS. Severe cases progress to cardiac arrest.
Management
The combination is appropriate in heart failure with reduced ejection fraction. Check potassium and creatinine 1 week after start, then monthly. If potassium exceeds 5.5 mmol/L, reduce the dose of one agent.
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