The influence of fluvastatin, a liver-selective, competitive inhibitor of the 3-hydroxymethyl-glutaryl-coenzyme A reductase, on the lipoprotein metabolism was investigated in 9 patients with nephrotic syndrome. All patients had biopsy-proven renal disease as cause of their nephrotic syndrome and exhibited severe hyperlipidemia [baseline: serum cholesterol 358 ± 46 mg/dl (9.3 mmol/l), low-density lipoprotein cholesterol 236 ± 18 mg/dl (6.1 mmol/l), triglyerides 333 ± 28 mg/dl (3.8 mmol/l), and lipoprotein Lp(a) 46 ± 11 mg/dl]. After 1 year of 40 mg of fluvastatin, significant reductions of total cholesterol by 31% to 242 ± 26 mg/dl (6.3 mmol/l) and low-density lipoprotein cholesterol by 29% to 162 ± 12 mg/dl (4.2 mmol/l) were observed. Furthermore, triglyceride values were also lowered significantly by 19% to 268 ± 21 mg/dl (3.1 mmol/l). Lipoprotein Lp(a) and high-density lipoprotein-cholesterol remained unchanged by fluvastatin. These improvements in lipid profile were maintained during the entire follow-up period of 1 year. There were no adverse events, and the slight increase in serum creatinine observed during the study was considered to be due to the primary renal disease. In conclusion, long- term administration of fluvastatin in patients with nephrotic syndrome appears to be an effective and safe treatment of the hyperlipidemia associated with this disorder.