Nitrofurantoin

Nitrofurantoin is a broad spectrum antibacterial agent, active against the majority of urinary pathogens. It is bactericidal in renal tissue and throughout the urinary tract. The wide range of organisms sensitive to the bactericidal activity include:

Escherichia coli
Enterococcus Faecalis
Klebsiella Species
Enterobacter Species
Staphylococcus Species e.g. S. Aureus, S. Saprophyticus, S. Epidermidis
Citrobacter Species

Clinically, most common urinary pathogens are sensitive to nitrofurantoin. Some strains of Enterobacter and Klebsiella are resistant. Nitrofurantoin is not active against most strains of Proteus species or Serratia species. All Pseudomonas strains are resistant.

Absorption

Orally administered nitrofurantoin is readily absorbed in the upper gastrointestinal tract and is rapidly excreted in the urine. Blood concentrations at therapeutic dosages are usually low.

Distribution

Plasma nitrofurantoin concentrations at therapeutic doses of the nitrofurantoin capsule are low, with peak levels usually less than 1 mcg/ml. Nitrofurantoin is highly soluble in urine to which it may impart a brown colour. Unlike many drugs the presence of food or agents delaying gastric emptying increases the bioavailability of the nitrofurantoin capsule.

Elimination

Approx. 20-25% of the total single dose of nitrofurantoin prolonged-release capsule is recovered from the urine unchanged over 24 hours.

Maximum urinary excretion usually occurs 2-4 hours after administration of nitrofurantoin tablet. Urinary drug dose recoveries of about 40-45% are obtained. It has an elimination half-life of about 30 minutes.

None stated.