Reduced by bacterial flavoproteins into reactive intermediates that inactivate or alter ribosomal proteins and other macromolecules, inhibiting protein, DNA, RNA, and cell wall synthesis.

Treatment of urinary tract infections caused by susceptible strains of E. coli, enterococci, Staphylococcus aureus, and some Klebsiella and Enterobacter species.

• Adults: 50–100 mg four times daily.

• Pediatrics: 5–7 mg/kg/day in four divided doses.

• Long-term: Adults 50–100 mg at bedtime; Pediatric 1 mg/kg/day in single or divided doses.

Pulmonary reactions (acute, subacute, chronic)

Hepatic issues (hepatitis, jaundice, hepatic necrosis)

Peripheral neuropathy

Gastrointestinal issues (nausea, vomiting)

Dermatologic and allergic reactions

Hematologic abnormalities (e.g., anemia, leukopenia)

Anuria, oliguria, or significant renal impairment (CrCl <60 mL/min)

Pregnancy at term, labor/delivery, or neonates under 1 month

History of nitrofurantoin-induced jaundice or hepatic dysfunction

Known hypersensitivity to nitrofurantoin

Risk of severe pulmonary and hepatic reactions

Peripheral neuropathy risk in renal impairment or other predispositions

Risk of hemolysis in G6PD deficiency

C. difficile-associated diarrhea

Use with caution in elderly and during long-term therapy