Sulbenicillin-induced kaliuresis in man

The mechanism of kaliuresis induced by massive antibiotic administration was studied using alpha-sulfobenzyl penicillin (SBPC). In experimental group (n = 8), urinary electrolytes excretion were compared between following the infusion of 10 g SBPC in 200 ml water at a constant rate and following the infusion of 48 mmol of NaCl (equal to that contained in 10 g SBPC) in 200 ml water. For the control group, 96 mmol NaCl in 400 ml water was infused (n = 5). In the experimental group, urinary Na (UNaV) and urinary K excretion (UKV) increased relative to the control period. In the control group, UKV was not increased although UNaV was increased (p less than 0.05). UKV following SBPC infusion was correlated with UNaV (p less than 0.05) and urinary SBPC excretion (p less than 0.05). The ratio of urinary anion gap to urinary cation [1-(urinary Cl concentration/(urinary Na concentration + urinary K concentration))] was significantly increased following SBPC infusion (p less than 0.005) but not in the control group. This increase in anion gap is possibly due to urinary SBPC, which will be ionized over 90% as nonreabsorbable anion in maximally acidic urine. We conclude that the kaliuresis induced by massive SBPC administration in man is probably caused by the nonreabsorbable anion effect of SBPC itself.