The present study was undertaken to evaluate the effects of platelet activating factor (PAF) antagonists on nephrotoxicity induced by gentamicin (GENTA) and cisplatin (DDP) in rats. PAF infusion provoked a 56% decline in single nephron (SN) GFR due to a decrease in glomerular plasma flow (QA, 55%), glomerular transcapillary hydraulic pressure (delta P, 13%), and glomerular ultrafiltration coefficient (Kf, 37%). Four days after a single dose of DDP (6 mg/kg, i.p.) we observed non-oliguric acute renal failure (ARF) with reduced SNGFR (45%), QA (46%) and delta P (10%) and unchanged Kf. GENTA administration for 10 days (40 mg/kg, i.p. daily) induced a decline in SNGFR (40%), QA (41%) and Kf (41%). Chronic treatment with a GENTA + PAF antagonist (BN 52021) partially prevented the decline in SNGFR (22%) by an amelioration in QA (25%) and Kf (13%). However, simultaneous treatment with DDP and BN 52063 completely prevented the ARF induced by DDP, normalizing all parameters of renal function. Thus, PAF may be a potential mediator involved in the nephrotoxicity induced by GENTA and DDP.