Melatonin for prevention of acute kidney injury in patients treated with intravenous polymyxin B: a double-blind, placebo-controlled randomized clinical trial.

Objectives: To evaluate the effect of melatonin versus placebo on the incidence of acute kidney injury (AKI) in patients treated with polymyxin B.

Methods: We performed a single-centre, double-blind, randomized clinical trial (NCT03725267) of 30-mg oral melatonin versus placebo for patients treated with intravenous polymyxin B. Patients aged ≥18 years receiving polymyxin B for ≤48 hours were eligible. Melatonin or placebo pills were administered until the end of polymyxin B treatment or for a maximum of 14 days. The main outcome was any level of AKI.

Results: Eighty-eight patients were randomized: 44 in the melatonin group and 44 in the placebo group. The study ended prematurely because of polymyxin B shortage during the COVID-19 pandemic. The patients' mean age was 63.6 ± 17.3 years, and 60.2% of the patients were men. Forty-six (52.3%, 23 in each group) patients developed AKI during the follow-up period. The incidence rate of AKI was 81.9/1000 and 77.4/1000 patients per day in melatonin and placebo groups, respectively (hazard ratio, 1.09; 95% CI, 0.61-1.94; p 0.78). Renal failure and 30-day mortality were similar between the groups. Moreover, the incidence of AKI was not different in pre-specified sub-groups.

Discussion: Melatonin initiated in the first 48 hours of therapy did not reduce the incidence of AKI in patients treated with polymyxin B.