From the Guidelines
The recommended dose and frequency of Macrobid (Nitrofurantoin) for uncomplicated urinary tract infections in adults is 100 mg taken orally every 12 hours for 5 days. This recommendation is based on the most recent and highest quality study, which suggests that a 5-day course of nitrofurantoin is an appropriate choice for therapy due to minimal resistance and propensity for collateral damage, with efficacy comparable to other antimicrobials 1.
Key Considerations
- The medication should be taken with food to increase absorption and reduce gastrointestinal side effects.
- Patients should be advised to stay well-hydrated during treatment and to avoid antacids containing magnesium trisilicate, as these can interfere with the absorption of nitrofurantoin.
- It's crucial to complete the full course of treatment as prescribed, even if symptoms improve before the medication is finished.
Rationale
The choice of nitrofurantoin is supported by guidelines from the American College of Physicians and the Infectious Diseases Society of America, which recommend short-course antibiotics with either nitrofurantoin for 5 days, trimethoprim–sulfamethoxazole for 3 days, or fosfomycin as a single dose for women with uncomplicated bacterial cystitis 1.
Important Notes
- Fluoroquinolones, although highly efficacious in 3-day regimens, have a high propensity for adverse effects and should be reserved for patients with a history of resistant organisms.
- The IDSA/European Society of Clinical Microbiology and Infectious Diseases guideline recommends treatment durations depending on the type of antibiotic, including 5 days of nitrofurantoin, 3 days of TMP–SMX, or a single dose of fosfomycin 1.
From the Research
Recommended Dose and Frequency of Macrobid (Nitrofurantoin)
- The recommended dose and frequency of Macrobid (Nitrofurantoin) for uncomplicated cystitis in women is 100 mg twice daily for 5-7 days 2.
- Another study suggests that nitrofurantoin sustained release 100 mg twice daily for 7 days is effective in treating acute lower urinary tract infections in adults 3.
- However, a review of international guidelines shows that the evidence base for the recommended 3-day course of nitrofurantoin at 100 mg twice daily is limited, and it is unclear if this duration is optimal 4.
- A study on the impact of dosing regimen, age, and renal function on drug exposure found that nitrofurantoin exposure was similar in patients receiving 50 mg q6h and 100 mg q12h, and was not affected by age and eGFR 5.
Considerations for Treatment
- The choice of antibiotic and duration of treatment should be individualized based on risk factors for resistance and regimen tolerability 2.
- Nitrofurantoin is generally well tolerated, but common adverse events include mild headache and rash 3.
- The development of resistance to nitrofurantoin is low, making it a suitable option for treating acute urinary tract infections 3.