From the Guidelines
Nitrofurantoin 500mg is primarily used to treat urinary tract infections (UTIs) caused by susceptible bacteria, with a recommended dosage of 100mg taken twice daily for 5 days, as stated in the American College of Physicians' best practice advice 1.
Uses of Nitrofurantoin
- Treatment of uncomplicated bacterial cystitis in women
- Treatment of uncomplicated pyelonephritis in men and women, although fluoroquinolones or trimethoprim-sulfamethoxazole are preferred options 1
Dosage and Administration
- The typical dosage for acute uncomplicated UTIs in adults is 100mg taken twice daily for 5 days, so the 500mg strength would not be a standard single dose
- Nitrofurantoin should be taken with food to improve absorption and reduce stomach upset
Mechanism of Action and Efficacy
- Nitrofurantoin works by damaging bacterial DNA and inhibiting protein synthesis, making it effective against many common urinary pathogens including E. coli
- It concentrates in the urine, making it ideal for treating UTIs while minimizing systemic effects
- Clinical cure rates with nitrofurantoin range from 88% to 93%, and bacterial cure rates range from 81% to 92% 1
Safety and Precautions
- Nitrofurantoin is not recommended for patients with significant kidney impairment (creatinine clearance <30 mL/min) as it may not reach effective concentrations in the urine and could increase toxicity risk
- Common side effects include nausea, headache, and urine discoloration
- Patients should drink plenty of water while taking this medication to help flush the infection from the urinary tract
Guidelines and Recommendations
- The American College of Physicians recommends nitrofurantoin as a first-line treatment option for uncomplicated bacterial cystitis in women, with a 5-day course of 100mg twice daily 1
- The Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases also recommend nitrofurantoin as a treatment option for acute uncomplicated cystitis and pyelonephritis 1
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Uses of Nitrofurantoin
- Nitrofurantoin is used for the antibacterial therapy of uncomplicated urinary tract infections (UTI) 2
- It is effective against Escherichia coli and other pathogens of uncomplicated urinary tract infections such as Staphylococcus saprophyticus and Enterococcus species 2, 3, 4
- Nitrofurantoin has been recommended as a first-line antibiotic for the empiric antibacterial treatment of uncomplicated cystitis in otherwise healthy women 2, 5, 3
- It is also used for the re-infection prophylaxis of recurrent uncomplicated urinary tract infections 2, 6
- Nitrofurantoin is considered a good fluoroquinolone-sparing alternative to co-trimoxazole for the treatment of uncomplicated UTIs 3
- It is effective in treating UTIs caused by multi-drug resistant pathogens 4
Dosage and Administration
- The typical dosage of Nitrofurantoin is 500 milligrams, taken orally 2, 5, 3, 4, 6
- The frequency and duration of administration may vary depending on the specific condition being treated and the patient's response to therapy 2, 5, 3, 4, 6
Safety and Efficacy
- Nitrofurantoin has been shown to be effective in preventing UTIs, with a risk ratio of 0.38 in favor of nitrofurantoin compared to no prophylaxis 6
- Its prophylactic efficacy is superior to that of methenamine hippurate and comparable to that of other antibacterials 6
- However, nitrofurantoin may be associated with increased non-severe adverse effects, and severe adverse effects can occur infrequently 2, 6