Nitrofurantoin is a prescription antibacterial medication specifically designed to treat and prevent urinary tract infections (UTIs). As a nitrofuran derivative, it exerts its bactericidal effect primarily in the urinary tract, making it a focused therapeutic option for uncomplicated lower UTIs caused by susceptible strains of bacteria. Its unique pharmacokinetic profile allows for high concentrations in the urine with minimal systemic absorption, reducing the risk of widespread antibiotic resistance. Healthcare providers frequently prescribe nitrofurantoin for its reliable efficacy against common uropathogens like Escherichia coli, Enterococcus, and Staphylococcus saprophyticus.

Features

• Contains nitrofurantoin as the active pharmaceutical ingredient
• Available in immediate-release capsules (25 mg, 50 mg, 100 mg) and macrocrystalline/monohydrate extended-release formulations
• Bactericidal mechanism: disrupts bacterial ribosomal proteins, inhibits acetylcoenzyme A, and interferes with cell wall synthesis
• Specifically concentrates in the urinary tract with low plasma levels
• Effective against both gram-positive and gram-negative uropathogens
• FDA-approved for treatment and prophylaxis of UTIs

Benefits

• Provides targeted antibacterial action directly in the urinary system
• Minimizes disruption to gut flora compared to broad-spectrum antibiotics
• Reduces recurrence risk when used for prophylactic purposes
• Established safety profile with decades of clinical use
• Convenient dosing regimen typically involving twice-daily administration
• Cost-effective treatment option for uncomplicated UTIs

Common use

Nitrofurantoin is primarily indicated for the treatment of acute uncomplicated urinary tract infections (cystitis) caused by susceptible strains of Escherichia coli, Enterococcus faecalis, Staphylococcus saprophyticus, and certain strains of Klebsiella and Enterobacter species. It is particularly valuable for patients who cannot tolerate other first-line antibiotics or when local resistance patterns favor its use. The medication is also approved for long-term suppressive therapy in patients with recurrent UTIs, typically at a reduced dosage taken once daily at bedtime. It is not indicated for the treatment of pyelonephritis or perinephric abscesses due to inadequate tissue penetration.

Dosage and direction

For acute uncomplicated UTIs in adults and children ≥12 years: 50-100 mg orally four times daily (immediate-release) or 100 mg twice daily (macrocrystalline) for 5-7 days. For prophylaxis: 50-100 mg orally once daily at bedtime. Pediatric dosing (≥1 month): 5-7 mg/kg/day divided into four doses (maximum 400 mg/day). Take with food or milk to enhance absorption and minimize gastrointestinal upset. Complete the full prescribed course even if symptoms improve earlier. Do not crush or chew capsules; swallow whole with a full glass of water. Dosage adjustment is required in patients with renal impairment (CrCl <60 mL/min).

Precautions

Use with caution in patients with renal impairment (contraindicated if CrCl <60 mL/min), diabetes, electrolyte imbalance, vitamin B deficiency, or debilitating disease. Monitor renal function periodically during prolonged therapy. May cause pulmonary reactions (acute, subacute, or chronic pulmonary hypersensitivity); discontinue immediately if respiratory symptoms develop. Hemolytic anemia may occur in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Peripheral neuropathy has been reported, risk increases with renal impairment, anemia, diabetes, electrolyte imbalance, vitamin B deficiency, or debilitating disease. May cause tooth discoloration (yellow-brown) in children; dental hygiene should be maintained during treatment. Superinfections with nonsusceptible organisms may occur.

Contraindications

Patients with known hypersensitivity to nitrofurantoin or other nitrofuran derivatives. Significant renal impairment (creatinine clearance <60 mL/min) due to inadequate urinary concentrations and increased risk of toxicity. Patients with history of cholestatic jaundice or hepatic dysfunction associated with prior nitrofurantoin use. Infants under one month of age (risk of hemolytic anemia). Pregnancy at term (38-42 weeks gestation), during labor and delivery, or when onset of labor is imminent. Patients with history of nitrofurantoin-associated pulmonary reactions.

Possible side effect

Common: nausea, vomiting, loss of appetite, abdominal pain, diarrhea, headache, drowsiness. Less common: pulmonary reactions (cough, chest pain, dyspnea, pulmonary infiltration), peripheral neuropathy (paresthesia, numbness), hypersensitivity reactions (rash, pruritus, urticaria, angioedema), hepatic reactions (hepatitis, cholestatic jaundice), hematological effects (hemolytic anemia, megaloblastic anemia, granulocytopenia, thrombocytopenia). Rare: anaphylaxis, Stevens-Johnson syndrome, erythema multiforme, drug fever, arthralgia, pancreatitis, optic neuritis. Pseudomembranous colitis has been reported with nearly all antibacterial agents.

Drug interaction

Antacids containing magnesium trisilicate may reduce absorption and efficacy. Probenecid and sulfinpyrazone may inhibit renal tubular secretion, increasing nitrofurantoin serum levels and toxicity risk while decreasing urinary concentrations. Uricosuric agents may similarly affect excretion. May antagonize the antibacterial effects of nalidixic acid. Use with drugs that have neurotoxic potential may increase risk of peripheral neuropathy. Concurrent use with other antibiotics that cause bone marrow suppression may increase hematological toxicity risk.

Missed dose

If a dose is missed, take it as soon as remembered unless it is almost time for the next scheduled dose. Do not double the dose to make up for a missed one. Resume the regular dosing schedule. Maintaining consistent antibiotic levels is important for effectiveness, but occasional missed doses are unlikely to significantly impact treatment outcomes if the overall regimen is followed consistently.

Overdose

Symptoms may include nausea, vomiting, and gastrointestinal distress. No specific antidote exists. Treatment is supportive and symptomatic. Emesis may be induced if ingestion was recent and patient is conscious. Gastric lavage may be considered. Adequate hydration should be maintained to promote urinary excretion. Hemodialysis may be of limited value due to nitrofurantoin’s rapid elimination and protein binding. Management of potential complications such as neurotoxicity or hematological effects may require specialized care.

Storage

Store at controlled room temperature (20-25°C or 68-77°F) in the original container. Protect from light and moisture. Keep tightly closed. Do not store in bathroom or other areas with high humidity. Keep out of reach of children and pets. Do not use after expiration date printed on packaging. Properly discard any unused medication after completing treatment course.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting, changing, or stopping any medication. The prescribing physician should be aware of the patient’s complete medical history, current medications, and allergies. Individual response to medication may vary. Proper diagnosis and treatment selection should be made by a healthcare provider familiar with the patient’s specific condition.

Reviews

Clinical studies demonstrate nitrofurantoin’s efficacy in treating uncomplicated UTIs with success rates of 85-95% for susceptible organisms. Many urologists appreciate its targeted action and low resistance development compared to fluoroquinolones. Patients often report rapid symptom relief, though gastrointestinal side effects are commonly noted. Long-term prophylactic use shows significant reduction in UTI recurrence rates in susceptible populations. Some concerns exist regarding pulmonary and hepatic reactions with prolonged use, necessitating appropriate patient selection and monitoring.