Mefenamic acid nephropathy: an interstitial and mesangial lesion.

Six cases of acute renal failure associated with mefenamic acid therapy are described. Five patients were non-oliguric and five patients had clinical features of salt and water depletion. In these patients the presenting symptoms were abdominal pain, diarrhoea and vomiting. Renal biopsy in five patients showed interstitial nephritis and mesangial proliferation. All patients recovered without specific therapy after withdrawal of the drug, but in four patients mild renal impairment persisted. These findings indicate that both interstitial and mesangial changes are common features of acute renal failure due to mefenamic acid therapy.