[Severe Electrolyte Disorders During the Therapy of Heart Failure with the Therapy of Heart Failure with the ACE-inhibitor Enalapril]

Angiotensin I converting enzyme inhibition by captopril and enalapril may influence sodium and potassium homeostasis. In patients without cardiac failure and with normal renal function significant electrolyte disturbances rarely occur. We report on four patients who developed life-threatening electrolyte disturbances following treatment with enalapril for severe cardiac failure (NYHA-class II-IV). There were important concomitant factors in all four cases: in one case under additional medication with a thiazide diuretic and a nonsteroidal antiinflammatory, hyponatremia of 107 mmol/l occurred. In two further cases severe hyperkalemia of 7.4 and 7.3 mmol/l was observed in the presence of acute renal failure due to enalapril-induced hypotension and concomitant therapy with a nonsteroidal antiinflammatory drug respectively. In a fourth case the combination of enalapril with a potassium-sparing diuretic provoked severe hyperkalemia of 7.9 mmol/l.