From the Guidelines
Macrobid (nitrofurantoin monohydrate/macrocrystals) should be prescribed at a dose of 100 mg taken orally twice daily for 5 days for uncomplicated urinary tract infections, as recommended by the most recent guidelines 1. This dosing regimen is based on the latest evidence from the American College of Physicians, which suggests that a 5-day course of nitrofurantoin is an appropriate treatment for uncomplicated bacterial cystitis in women 1. The medication should be taken with food to improve absorption and reduce stomach upset. Patients should complete the entire prescribed course even if symptoms improve before finishing the medication. Macrobid works by damaging bacterial DNA and is effective against many common UTI-causing organisms, particularly E. coli. It concentrates in the urine, making it ideal for treating lower urinary tract infections. Some key points to consider when prescribing Macrobid include:
- Patients should drink plenty of water while taking this medication
- Potential side effects include nausea, headache, and urine discoloration
- Macrobid is not recommended for patients with significant kidney impairment (creatinine clearance <30 mL/min), during late pregnancy, or for those with G6PD deficiency
- If symptoms worsen or do not improve within 3 days, patients should contact their healthcare provider. The Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases also recommend nitrofurantoin as a first-line treatment for uncomplicated cystitis, with a dosing regimen of 100 mg twice daily for 5 days 1. However, the more recent guideline from the American College of Physicians 1 takes precedence in determining the optimal dosing regimen.
From the Research
Macrobid Dosing for UTI
- The recommended dosing for Macrobid (nitrofurantoin) in the treatment of urinary tract infections (UTIs) is not explicitly stated in the provided studies, but it is mentioned that a 5-day course of nitrofurantoin is a recommended first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females 2.
- A study from 2023 suggests that 3 days of nitrofurantoin at 100 mg twice daily is recommended as first-line treatment for uncomplicated UTI in evidence-based guidelines across the UK, but notes that there is little direct evidence to support this course length 3.
- Another study from 2016 compared the effects of nitrofurantoin vs other agents in reducing recurrent UTIs in adult women, and found that nitrofurantoin had similar efficacy but a greater risk of adverse events than other prophylactic treatments 4.
- The 2020 study also mentions that nitrofurantoin is a treatment option for UTIs due to AmpC- β-lactamase-producing Enterobacteriales, ESBLs-E coli, and ESBLs-Klebsiella pneumoniae 2.
- The 2002 study notes that ideal antimicrobial agents for UTI management have primary excretion routes through the urinary tract to achieve high urinary drug levels, and that nitrofurantoin is one such agent 5.
- The 1977 study mentions that sulfonamides, trimethoprim-sulfamethoxazole, nitrofurantoin, and nalidixic acid are excreted in the urine in high concentration and are active in vitro against usual aerobic gram-negative bacteria, making them useful for treatment of uncomplicated lower urinary tract infections 6.