Spontaneous relapse of naproxen-related nephrotic syndrome.

A number of nonsteroidal anti-inflammatory drugs cause nephrotoxicity characterized by nephrotic syndrome, usually with acute renal insufficiency. Remission of proteinuria and renal insufficiency after discontinuation of nonsteroidal anti-inflammatory drug therapy is characteristic. Relapse of nephrotic syndrome in the absence of nonsteroidal anti-inflammatory drug rechallenge has not previously been reported. Nephrotic syndrome developed in an 80-year-old woman taking naproxen, and remitted after discontinuation of the drug. Nephrotic syndrome relapsed four months later without re-exposure to naproxen or other nonsteroidal anti-inflammatory drugs. Renal biopsy at that time revealed minimal-change disease. The relationship between these two episodes of nephrotic syndrome is discussed with regard to possible pathogenetic mechanisms.