Nalidixic acid is a synthetic narrow spectrum antibacterial. It is bacteriostatic or bactericidal depending on the concentration. Nalidixic acid appears to act by inhibiting bacterial DNA synthesis, possibly by interfering with DNA polymerization. It is rapidly and completely absorbed from the G.I. Tract. Parent drug and active metabolites are distributed to most tissues specially to the kidney and to the urine.
Initial: Oral 1 gm every 6 hours for 7 days reducing to 500 mg every 6 hours.
Infants and children 3 month of age and over:
Initial: Oral 13.75 mg/kg body weight every six hours for one or two weeks.
Maintenance: Oral 8.25 mg/kg body weight every six hours or as prescribed by the physician.