Nitrofurantoin

ByBrian J. Werth, PharmD, University of Washington School of Pharmacy
Reviewed/Revised May 2024
View Patient Education

antibiotic; the exact mechanism is unknown.

Nitrofurantoin is available only for oral use.

Pharmacokinetics of Nitrofurantoin

Indications for Nitrofurantoin

Other species of enterococci, including vancomycin-resistant strains, and Klebsiella and EnterobacterProteus, Providencia, Morganella, Serratia, Acinetobacter, and Pseudomonas species are resistant. There is no cross-resistance with other antibiotic classes.

Nitrofurantoin is used only for

  • Treatment or prophylaxis of uncomplicated lower urinary tract infection (cystitis)

In women with recurrent urinary tract infections, it may decrease the number of episodes.

Nitrofurantoin is not effective for treatment of suspected pyelonephritis or systemic infection due to poor serum and tissue levels.

Contraindications to Nitrofurantoin

FDA-approved labeling states that nitrofurantoin is contraindicated in patients with a creatinine clearance < 60 mL/minute. However, data are lacking to support this recommendation, and studies have shown that short-term use of nitrofurantoin is generally well-tolerated and effective in patients with a creatinine clearance ≥ 30 mL/minute. However, higher adverse events have been reported in patients with renal insufficiency.

Use of Nitrofurantoin During Pregnancy and Breastfeeding

nitrofurantoin is generally considered to be safe during all 3 trimesters of pregnancy. However, nitrofurantoin is contraindicated at term and during labor or delivery because it interferes with immature enzyme systems in red blood cells of neonates, damaging the cells, and may result in hemolytic anemia.

Nitrofurantoin enters breast milk and should be avoided if possible during the first month of breastfeeding to reduce the risk of hemolytic anemia, especially in infants with hyperbilirubinemia.

Adverse Effects of Nitrofurantoin

  • Gastrointestinal disturbances

  • Pulmonary toxicity

  • Peripheral neuropathy

  • Hemolytic anemia

  • Hepatic toxicity

Common adverse effects are nausea and vomiting, which are less likely with the macrocrystalline form. Fever, rash, acute hypersensitivity pneumonitis (accompanied by fever and eosinophilia), and chronic progressive pulmonary interstitial fibrosis may occur. Paresthesias may result and may be followed by a severe ascending motor and sensory polyneuropathy if the antibiotic is continued, especially in patients with renal failure.

Leukopenia and hepatic toxicity (acute cholestatic or chronic active hepatitis) have been reported, and hemolytic anemia can occur in patients with G6PD deficiency and in infants < 1 month of age.

Chronic pulmonary and hepatic reactions occur when the antibiotic is used for > 6 months.

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