Protective effects of silymarin on preventing vancomycin nephrotoxicity in infectious patients: a randomized, double-blinded, placebo-controlled, pilot clinical trial

Abstract

Nephrotoxicity is one of the most common complications of vancomycin use in clinical practice. Silymarin has potential to be a renoprotective agent for nephrotoxic drugs due to its antioxidant, anti-inflammatory, and anti-apoptotic effects. The aim of this clinical study is evaluating the potential effects of silymarin on preventing vancomycin nephrotoxicity. A multicenter, randomized, double-blinded, placebo-controlled, clinical trial was conducted on patients with the indication of systemic vancomycin for at least 7 days. Patients were screened daily and those who met the inclusion criteria were selected and randomly assigned into either silymarin or placebo groups. Accordingly, 140 mg silymarin tablet (Livergol®) or placebo was given orally three times daily. Silymarin or placebo were provided in conjunction with vancomycin for at least 7 days. If vancomycin therapy was extended beyond 7 days, the administration of silymarin or placebo was continued until the end of vancomycin treatment. Malondialdehyde, glutathione, and total antioxidant capacity were measured in the serum on days 0 and 7. A trough level of vancomycin was assessed 30 min before the fifth dose of vancomycin. Acute kidney injury (AKI) was monitored in each patient daily during the course of vancomycin treatment. The causality assessment of all identified cases of vancomycin associated AKI was performed by the Naranjo scale. The primary endpoint was vancomycin nephrotoxicity. It was defined based on the KDIGO 2012 criteria for AKI as either an increase of 0.3 units or more in serum creatinine level during 48 h or 50% (1.5-fold) or more during 7 days compared to baseline values. During the study period, 34 patients in the silymarin group and 32 patients in the placebo group completed the clinical trial. Demographic, baseline clinical, and laboratory characteristics were comparable between placebo and silymarin groups. The number of patients with AKI on days 5, 6, 7, 11,12, 13, and 14 in the placebo group was significantly higher than that in the silymarin group (p-value < 0.05). The incidence of acute tubular injury on the day 5 and 7 of vancomycin treatment was significantly lower in the silymarin group (p-value = 0.005 and p-value = 0.032, respectively). Antioxidant indexes including serum total antioxidant capacity and glutathione significantly increased in the silymarin group (p-value < 0.001 for both indexes). In contrast, serum malondialdehyde as an end product of lipid peroxidation pathway significantly decreased in the silymarin group during 7 days (p-value < 0.001). The results of the present pilot, clinical trial suggested that silymarin co-administration may prevent vancomycin nephrotoxicity.

Keywords: Adverse reactions; Acute kidney injury; Drug related side effects; Nephrotoxicity; Prevention; Silymarin; Vancomycin.