From the Guidelines
Nitrofurantoin should be prescribed at a dose of 5 days for uncomplicated bacterial cystitis in women. This recommendation is based on the best practice advice from the American College of Physicians, as outlined in the 2021 study published in the Annals of Internal Medicine 1. The study suggests that for women with uncomplicated bacterial cystitis, clinicians should prescribe short-course antibiotics with either nitrofurantoin for 5 days, trimethoprim–sulfamethoxazole (TMP–SMZ) for 3 days, or fosfomycin as a single dose. Some key points to consider when prescribing nitrofurantoin include:
- The medication should be taken with food to enhance absorption and reduce gastrointestinal side effects
- The standard dose is typically 100 mg twice daily for 5 days
- Nitrofurantoin achieves high concentrations in urine but not in bloodstream, making it suitable only for lower urinary tract infections
- The medication should be avoided in patients with creatinine clearance below 60 ml/min, during pregnancy near term, in nursing mothers, and in those with G6PD deficiency, as noted in general clinical practice guidelines, although not explicitly stated in the study 1. It is essential to note that the study focuses on uncomplicated UTIs, and the treatment approach may vary for complicated cases or in patients with specific underlying conditions. In clinical practice, it is crucial to consider the patient's individual needs, medical history, and potential interactions with other medications when prescribing nitrofurantoin or any other antibiotic. The goal of treatment is to effectively manage the infection while minimizing the risk of adverse effects and promoting the best possible outcome in terms of morbidity, mortality, and quality of life.
From the Research
Recommended Dose of Nitrofurantoin for UTI
- The recommended dose of Nitrofurantoin for Urinary Tract Infection (UTI) is a 5-day course 2, 3 or 7 days 4, 3.
- The specific dosage is 100 mg twice daily for 5-7 days 3.
- A 5-day course of Nitrofurantoin is considered a first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females 2.
- Nitrofurantoin exposure is not significantly affected by age and renal function, as shown in a study where urine nitrofurantoin exposure was similar in patients receiving 50 mg q6h and 100 mg q12h, regardless of age and eGFR 5.
Considerations for Renal Function
- The contraindication of Nitrofurantoin in patients with a creatinine clearance (CrCl) below 60 mL/min is not supported by evidence 6.
- Data suggest that Nitrofurantoin can be used in patients with a CrCl of 40 mL/min or higher 6.
- However, concerns of increased risks of serious adverse reactions in patients with reduced renal function have limited the use of Nitrofurantoin, particularly with prolonged treatment, genetic variability, and predisposition to hypersensitivity 6.