BackgroundContrast-induced nephropathy (CIN) is one of the common hospital-acquired acute renal failures. The purpose of this study was to investigate whether Coenzyme Q10 (CoQ10) and trimetazidine (TMZ) can prevent the occurrence of CIN after elective cardiac catheterization in patients with coronary artery disease complicated with renal dysfunction.MethodsConsecutive coronary artery disease patients with renal insufficiency scheduled for coronary angiography were enrolled in randomized, paralleled, double-blind, controlled trial. The development of CIN was occurrence at the 48 or 72 h after the procedure. The changes of serum creatinine (SCr), eGFR, and Cys-C within 72 h after the procedure were measured and compared. In vivo contrast medium (CM)-induced acute kidney injury (AKI) animal model was established, and CoQ10 plus TMZ was orally administrated to evaluate its renal protective effect.Results150 patients with renal insufficiency were enrolled finally. CIN occurred in 21 (14.00%) of the 150 patients. 72 h after the procedure, the incidence of CIN was significantly lower in CoQ10 plus TMZ group compared with control group (6.67 vs. 21.3%, p = 0.01). No cardiac death occurred in this study. No side effects were observed after administration of CoQ10 and TMZ. In vivo test demonstrated that CoQ10 and TMZ could significantly reduce the concentration of blood urea nitrogen (BUN) and SCR induced by CM i.v. injection, as well as tubular pathological injuries. Meanwhile, CoQ10 and TMZ could significantly reduce the oxidation stress in kidneys from CM-AKI animals.ConclusionCoQ10 plus TMZ could decrease the incidence of CIN in patients with renal insufficiency undergoing elective cardiac catheterization, and their effect may be due to its strong anti-oxidation effect.