We studied the actions of nifedipine and the platelet activating factor (PAF) antagonist BN 52021 on renal and tubular function in glycerol-induced acute renal failure (Gly-ARF). The tubular handling of sodium was evaluated through the lithium clearance method in awake rats in metabolic cages. The sequential analysis of tubular function 3, 6, 12, and 24 h after Gly-ARF showed a sharp decrease in fractional proximal Na reabsorption (FPRNa—control 74.1±12.5%, 3 h: 79.5±6.0%; 6 h: 41.8±15.9%; 12 h: 22.9±17.9%; and 24 h: 31.1±16.2% (p<0.001) while fractional distal Na reabsorption (FDRNa) did not change during the study. The effect of nifedipine (20 mg/kg p.o.) and BN 52021 (1 mg/kg i.p.) were evaluated 24 h after the induction of Gly-ARF. Both drugs attenuated the reduction in creatinine clearance (control 431.8±108.2, glycerol 96.7±43.8, glycerol plus nifedipine 264.9±103.5, and glycerol plus BN 52021 188.9±69.8μL/min/100 g, p<0.001). However, only nifedipine could keep FPRNahigher than untreated rats (58.3±13.2 vs. 31.1±16.2%, p<0.05) and reduced the tubular necrosis on histologic semiquantitative analysis. Our data showed that nifedipine and BN 52021 could protect against filtration failure in Gly-ARF but that only nifedipine reduced the proximal tubular lesion.