The ameliorative effect of calcium channel blockers (CCBs) and a phospholipase-A₂ inhibitor in drug-/chemical-induced nephrotoxicity was investigated. Rats were divided into 7 groups of 5 rats in each group. In the gentamicin model, group I rats were pretreated with normal saline (10 ml kg⁻¹), while groups II–VII rats were pretreated with normal saline (10 ml kg⁻¹), ascorbic acid (10 mg kg⁻¹), nifedipine (0.86 mg kg⁻¹), verapamil (4.3 mg kg⁻¹), diltiazem (3.43 mg kg⁻¹), and prednisolone (0.57 mg kg⁻¹), respectively, perorally 1 h before intraperitoneal (i.p.) injection of gentamicin (40 mg kg⁻¹) for 14 days. In the carbon tetrachloride (CCl₄) model, rats were pretreated with CCBs and prednisolone for 7 days before inducing nephrotoxicity with 20% CCl₄ (1.5 ml kg⁻¹). Rats were thereafter killed and blood and tissue samples were collected for assessments. I.p. injections of gentamicin and CCl₄ caused significant hypernatremia, hypokalemia, hypocalcemia, hypophosphatemia, and hyperchloremic alkalosis and reduced renal tissue levels of antioxidants. Also, significant reductions in the hemoglobin, packed cell volume, red blood cells, and platelet indices were observed. Pretreatments with nifedipine (0.86 mg kg⁻¹), verapamil (4.3 mg kg⁻¹), diltiazem (3.43 mg kg⁻¹), and prednisolone (0.57 mg kg⁻¹) significantly ameliorated the deleterious effects of gentamicin and CCl₄ possibly via antioxidant and anti-lipoperoxidation mechanisms. The results obtained in this study suggest potential clinical usefulness of tested CCBs and prednisolone in drug-/chemical-induced nephrotoxicity.