Effects of oral neomycin and kanamycin in chronic uremic patients: II. Nitrogen balance.

Nitrogen balance was studied for five to seven days before and during oral administration of neomycin or kanamycin to 14 patients with severe chronic renal failure who were receiving long-term nutritional therapy consisting of protein restriction and supplements of essential amino acids or their nitrogen-free analogues. There was a significant improvement in nitrogen balance during the antibiotic period when compared to the control period, averaging +0.80 g of N per day (P less than 0.005). There was no significant change in average dietary nitrogen, fecal nitrogen, the excretion of non-urea urinary nitrogen, or urea appearance (defined as the sum of urinary urea and the change in the urea pool) during the antibiotic period. However, total nitrogen intake increased by 0.47 g per day owing to nitrogen contained in the drugs. The lack of a change in fecal nitrogen implies that fecal nitrogen not attributable to the drug must have fallen substantially. We conclude that oral neomycin and kanamycin may improve nitrogen balance in patients with severe chronic renal failure by diminishing endogenous fecal nitrogen.