Furosemide is a diuretic. Long-term use of furosemide may cause electrolyte disorders, decreased blood volume, risk of thrombosis, and cardiac arrhythmia in patients. 1. Electrolyte disorders: As furosemide is a strong diuretic, while diuretic, it also discharges potassium ions and sodium ions from the blood, long-term use of furosemide will lead to a decrease in blood potassium, and patients are prone to hypokalemia. 2. Decrease in blood volume: the most important role of furosemide is diuretic, long-term use, a large amount of urine discharge, resulting in a reduction of water in the blood, the patient’s blood volume is reduced, and some patients may experience symptoms of hypotension. 3. Thrombosis risk: Due to the large amount of urine discharge, body fluids decrease, blood volume decreases, the viscosity of the blood increases, red blood cells and platelets are easy to aggregate, resulting in an increased risk of thrombosis. 4. Cardiac arrhythmia: due to electrolyte disorders, patients may develop hypokalemia, which will aggravate the risk of cardiac arrhythmia. All of the above medications should be used under doctor’s supervision, avoid self-medication.