Overview
Nitrofurantoin is an antibacterial agent specifically indicated for the treatment of uncomplicated urinary tract infections caused by susceptible strains of Escherichia coli, Staphylococcus aureus, Klebsiella, Enterobacter, and enterococci. It is not effective for pyelonephritis or perinephric abscesses due to its limited tissue distribution. The drug should be administered with food to improve absorption and patient tolerance.
Mechanism of Action
Nitrofurantoin is a synthetic nitrofuran derivative that exerts antibacterial activity through multiple mechanisms. It is reduced by bacterial nitroreductases to reactive intermediates that damage bacterial DNA, inhibit protein synthesis, and disrupt other cellular processes, leading to bacterial cell death.
Indications
- Treatment of uncomplicated urinary tract infections caused by susceptible strains of Escherichia coli, Staphylococcus aureus, Klebsiella, Enterobacter, and enterococci
Common Doses
- 50 mg
- 100 mg
Dosage
Administer with food to improve absorption and tolerance. Typical adult dosage is 50-100 mg four times daily for 7 days, or 100 mg twice daily for 7 days for macrocrystal formulation.
Contraindications
- Anuria, oliguria, or significant renal impairment (creatinine clearance <60 mL/min)
- Pregnancy at term (38-42 weeks gestation), during labor and delivery, or when onset of labor is imminent
- Neonates under one month of age
- Previous history of cholestatic jaundice or hepatic dysfunction associated with nitrofurantoin
- Known hypersensitivity to nitrofurantoin
Side Effects
- Nausea, vomiting, diarrhea
- Headache, dizziness
- Pulmonary reactions (cough, dyspnea, chest pain)
- Hepatic reactions (jaundice, hepatitis)
- Peripheral neuropathy
- Hypersensitivity reactions (rash, pruritus, urticaria)
- Hemolytic anemia in G6PD-deficient patients
Interactions
- Antacids containing magnesium trisilicate reduce absorption of nitrofurantoin
- Uricosuric drugs (probenecid, sulfinpyrazone) increase serum nitrofurantoin levels and decrease urinary levels, potentially increasing toxicity and reducing efficacy
Counseling Points
- Take with food or milk to improve absorption and reduce stomach upset
- Complete the full course of therapy even if symptoms improve
- Report any signs of breathing difficulty, cough, chest pain, or yellowing of skin/eyes immediately
- Avoid antacids containing magnesium trisilicate while taking this medication
- Drink plenty of fluids unless otherwise directed by your healthcare provider