Nitrofurantoin is a bactericidal antibiotic Overview of Antibacterial Drugs Antibacterial drugs are derived from bacteria or molds or are synthesized de novo. Technically, “antibiotic” refers only to antimicrobials derived from bacteria or molds but is often (including... read more ; the exact mechanism is unknown.
Nitrofurantoin is available only for oral use.
After a single dose of nitrofurantoin, serum drug levels are very low, but urine drug levels are therapeutic.
Indications for Nitrofurantoin
Nitrofurantoin is active against common uropathogens, such as
Other species of enterococci, including vancomycin-resistant strains, and Klebsiella and Enterobacter species are often less susceptible, but nitrofurantoin may still be effective in treating uncomplicated cystitis caused by these pathogens. Most strains of Proteus, 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 Cystitis Bacterial urinary tract infections (UTIs) can involve the urethra, prostate, bladder, or kidneys. Symptoms may be absent or include urinary frequency, urgency, dysuria, lower abdominal pain... read more )
In women with recurrent urinary tract infections, it may decrease the number of episodes.
Contraindications to Nitrofurantoin
Contraindications to nitrofurantoin use include
Previous allergic reaction to it
Renal insufficiency (creatinine clearance 60 L/minute)
Age < 1 month
Pregnancy at term (38 to 42 weeks gestation), during labor and delivery, or when the onset of labor is imminent.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked enzymatic defect common in people with African ancestry that can result in hemolysis after acute illnesses or intake of oxidant... read more
Use During Pregnancy and Breastfeeding
Animal reproduction studies with nitrofurantoin have not shown risk to the fetus. No adequate and well-controlled studies have been done in pregnant women, but 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
Adverse effects of nitrofurantoin include
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 drug 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 drug is used for > 6 months.