[Laxative abuse, plasma potassium levels and chronic interstitial nephritis due to phenacetin abuse (author's transl)].

In 154 patients with phenacetin nephropathy and in 26 patients with phenacetin abuse but without nephropathy a laxative abuse was observed in 3.2% and 15.4%, hypokalemia (3.5 maequ/l or less) in 9.1% and 3.9, respectively. The mean plasma potassium concentration was normal in both groups (4.45 and 4.22 maequ/l, respectively). These data do not support the recently proposed hypothesis that the simultaneous abuse of laxatives contributes to the development of analgesic nephropathy, and that the absence of laxative intake might explain the lack of renal damage in some phenacetin abusers. Although it cannot be excluded that long-standing potassium deficiency in consequence of an abuse of laxatives or diuretics exerts an additional nephrotoxic effect in some cases, this mechanism seems not to be involved in the majority of patients with phenacetin nephropathy.