Drug therapy reviews: Nalidixic acid

Abstract

The mechanism of action, antibacterial activity, pharmacokinetics, drug interactions, dosage, adverse reactions and therapeutic uses of nalidixic acid, a drug used to treat bacterial urinary tract infections, are reviewed. The usual adult dosage of nalidixic acid is 1 g four times daily; the pediatric dosage is 60 mg/ kg/day, divided into four equal doses. The drug is absorbed rapidly after oral administration and reaches peak blood concentrations in twd to four hours. The daily urinary recovery of administered drug is approximately 80% at steady state. Adverse reactions to nalidixic acid develop frequently, occur more readily with prolonged administration and have potentially serious consequences. Common reactions include gastrointestinal disturbances, skin lesions and neurological events such as tremulousness, confusion, drowsiness, headache and dizziness. Nalidixic acid is an alternative form of therapy for the penicillin-sensitive, cephalosporinsensitive or sulfonamide-sehsitive adult who has a recurrent urinary tract infection caused by susceptible Escherichia coli, Proteus sp and Enterobacter sp, uncomplicated by bacteremia. The drug should not be prescribed for patients with acute symptomatic urinary tract infections. Insufficient data are available to justify use of nalidixic acid as a prophylactic agent. The drug should not be administered to pregnant women.