Furosemide‐induced haemolytic anaemia in an extreme elderly patient

Furosemide, a loop diuretic, is commonly used to treat fluid overload symptoms and heart failure. Drug‐induced immune haemolytic anaemia is an unusual drug‐adverse event. Furosemide‐induced haemolysis is even rarer. This case report presents a 91‐year‐old male who developed acute haemolytic anaemia 3 days after initiating furosemide to treat myocardial infarction complicated with acute decompensated heart failure. He had increased lactate dehydrogenase and unconjugated bilirubin with undetectable haptoglobin, which indicated the destruction of red blood cells. Other causes for haemolytic anaemia, including hereditary, microangiopathic haemolytic anaemia, and paroxysmal nocturnal haemoglobinuria, were also excluded. He improved with drug cessation and a short course of glucocorticoids. This report aims to raise awareness of this rare complication caused by commonly prescribed drugs. Despite a negative result of a direct antiglobulin test, physicians must remain suspicious of drug‐induced immune haemolytic anaemia in unclear cases of haemolysis.