[Nalidixic acid: urinary levels during short-term therapy with reduced doses]

The acute inflammation of the lower afferent urinary tract is a superficial mucosal infection so long as structural and functional anomalies are excluded. A single or brief administration of antibacterially active substances with high urine concentrations can shorten uncomplicated attacks of infection and diminish the symptoms. The investigation of the urinary concentration of biologically active metabolites after administration of a daily dose of 2 g nalidixic acid revealed values which ensure that the minimum inhibitory concentrations in the afferent urinary tract are exceeded. The different responsiveness of the fluorimetric and microbiological methods applied for determination of the biologically active substances in urine led to results which were well correlated.