Is furosemide a nephrotoxic for hospitalized patients?

Introduction: Acute kidney disease (AKI) is preventable in certain situations. Long-term and/or high dose furosemide may lead to acute kidney injury. Objectives: We aimed to find the risk of AKI among hospitalised patients who were exposed to furosemide. Patients and Methods: This is a retrospective cohort study of hospitalised patients who received furosemide therapy during the admission between 2019 and 2021. Exposure to furosemide was grouped into low dose (≤ 40 mg/d) or high dose (>40 mg/d) and short-term use (≤ 72 hours) or long-term use (>72 hours). Risk of acute kidney injury was calculated as odds ratios with a 95% confidence interval (CI). A P value <0.05 was considered statistically significant. Results: Of 314 patients who received furosemide intravenously or orally, 197 patients (62.7%) had acute kidney injury. Of 197 patients with acute kidney injury, 110 patients (55.9%) received the dosage of >40 mg/d and 121 patients (61.4%) were on furosemide for >7 days (odds ratios [ORs]: 5.46, 95% CI: 3.17 to 9.39, P≤0.001 and ORs: 7.72, 95% CI: 4.4 to 13.52, P≤0.001). In comparison, the 87 (44.1%) patients who received ≤40 mg/d of furosemide had a lower incidence of AKI (ORs: 0.25, 95% CI: 0.13 to 0.48, P≤0.001) and only 21 of the patients (10.6%) who received furosemide for < 7 days were found to have acute kidney injury (ORs: 0.08, 95% CI: 0.04 to 0.14, P≤0.001). The combined effect of high dose and long-term furosemide therapy is more consequential as we found that 100 (31.8%) patients who received furosemide >40 mg for >72 hours, 96 patients (30.6%) developed AKI (ORs: 26.8, 95% CI: 9.53 to 75.63, P≤0.001). Conclusion: Among hospitalised patients, exposure to high dose furosemide or prolonged use of furosemide is associated with AKI. The risk is more when high dose furosemide is administered for longer than 72 hours. Presence of underlying diabetes, hypertension, cardiac failure and chronic kidney disease, are also associated with furosemide -induced hospital-acquired acute kidney injury.