Introduction
Nalidixic acid is a synthetic 1,8-naphthyridine antimicrobial agent with a limited bacteriocidal spectrum. It is an inhibitor of the A subunit of bacterial DNA gyrase.
Uses
Nalidixic acid is a quinolone antibiotic used to treat urinary tract infections.
For the treatment of urinary tract infections caused by susceptible gram-negative microorganisms, including the majority of E. Coli, Enterobacter species, Klebsiella species, and Proteus species.
Associated Conditions
Pharmacodynamics
Nalidixic acid is a quinolone antibacterial agent for oral administration. Nalidixic acid has marked antibacterial activity against gram-negative bacteria including Enterobacter species, Escherichia coli, Morganella Morganii; Proteus Mirabilis, Proteus vulgaris, and Providencia rettgeri. Pseudomonas species are generally resistant to the drug. Nalidixic acid is bactericidal and is effective over the entire urinary pH range. Conventional chromosomal resistance to nalidixic acid taken in full dosage has been reported to emerge in approximately 2 to 14 percent of patients during treatment; however, bacterial resistance to nalidixic acid has not been shown to be transferable via R factor.
Mechanism of Action
Evidence exists for Nalidixic acid that its active metabolite, hydroxynalidixic acid, binds strongly, but reversibly, to DNA, interfering with synthesis of RNA and, consequently, with protein synthesis.
Absorption
Following oral administration, nalidixic acid is rapidly absorbed from the gastrointestinal tract. Bioavailability is approximately 96%. Absorption may be delayed if taken with antacids.
Protein Binding
Nalidixic acid is 93% bound to protein in the blood, and the active metabolite, hydroxynalidixic acid is 63% bound.
Route of Elimination
Following oral administration, NegGram is rapidly absorbed from the gastrointestinal tract, partially metabolized in the liver, and rapidly excreted through the kidneys. Approximately four percent of NegGram is excreted in the feces.
Half Life
1.1 to 2.5 hours in healthy adult patients, and up to 21 hours in patients with impaired renal function.
Toxicity
ORAL (LD50): Acute: 1160 mg/kg [Rat]. 572 mg/kg [Mouse]. Toxic psychosis, convulsions, increased intracranial pressure, or metabolic acidosis may occur in patients taking more than the recommended dosage. Vomiting, nausea, and lethargy may also occur following overdosage.
Food Interactions
- Drink plenty of fluids.
- Take with food. Food reduces irritation.
Dosage
Children: Infants and children 3 month of age and over Initial: Oral 13.75 mg per kg body weight every six hours for one or two weeks. Maintenance: Oral 8.25 mg per kg body weight every six hours or as prescribed by the physician.
