Kidney toxicity of 3-methylxanthine in the rat.

The effects of 3-methylxanthine, the pharmacologically active metabolite of theophylline, on the kidneys of Wistar rats after short-term administration were studied. 3-Methylxanthine was administered in oral doses of 0 (control), 50, 100 and 200 mg per kg per day for 1, 8 and 16 days. The kidneys were examined by light and electron microscopy. Tubular necrosis was noticed at a dose level of 100 mg kg-1 after 16 days and at a dose level of 200 mg kg-1 after 8 days. Elevated values of serum urea were found after 1 day of treatment with a dose of 200 mg kg-1 and after 16 days with a dose of 100 mg kg-1. Elevated values of serum creatinine were detected after 8 days of treatment with a dose of 200 mg kg-1. The results indicate dose- and time-related renal failure following administration of 3-methylxanthine.