A Comparative Study of the Levels of Nalidixic Acid in Plasma and Urine and Its Antibacterial Activity in Urinary

NALIDIXIC ACID, one of a series of 1, 8naphthyridine derivatives with antibacterial activity was synthesised by Lesher, Froelich, Gruett, Bailey and Brundage (1962). Chemically it is l-ethyl-7-methyl-1, 8-naphthyridine-4-one3-carboxylic acid. The pharmacology and toxicology have been documented by Ward-McQuaid, Jichlinski and Macis (1963) and Lishman and Swinney (1963), based on unpublished information made available by the Sterling-Winthrop Research Institute. McChesney, Froelich, Lesher, Crain and Rosi (1964) have carried out studies of urine levels of nalidixic acid in healthy volunteers, in addition to a large series of animal experiments. It was found that nalidixic acid attained higher concentrations in human urine and animal kidney tissue than in any other body fluids or organs respectively. The effect of nalidixic acid on urinary tract infections has been studied in vitro by Deitz, Froelich and Bailey (1962) and clinically and bacteriologically by Buchbinder, Webb, Anderson and McCabe (1962), Barlow (1963), Carroll (1963), Jameson and Swinney (1963), Lishman and Swinney (1963), McCabe (1963), Slade (1963), Thompson and Rae (1964) and Ward-McQuaid and co-workers (1963). On the basis of this information we have examined 16 cases in the Liverpool Regional Paraplegic Centre at Southport to estimate the plasma and urine levels of nalidixic acid in patients, and its effect on bacteriological clearance.