What is the typical dose of Macrobid (nitrofurantoin) for treating a urinary tract infection (UTI)?

Nitrofurantoin (Macrobid) Dosing for Urinary Tract Infection

For treating uncomplicated urinary tract infections (UTIs), the recommended dose of nitrofurantoin (Macrobid) is 100 mg twice daily for 5 days. 1

First-Line Treatment Options for UTI

Nitrofurantoin is considered a first-line treatment for uncomplicated cystitis along with:

• Nitrofurantoin formulations and dosing:

  • Nitrofurantoin macrocrystals: 50-100 mg four times daily for 5 days 1
  • Nitrofurantoin monohydrate or macrocrystals: 100 mg twice daily for 5 days 1
  • Nitrofurantoin macrocrystals prolonged release: 100 mg twice daily for 5 days 1

• Other first-line options:

  • Fosfomycin trometamol: 3 g single dose 1
  • Pivmecillinam: 400 mg three times daily for 3-5 days 1

Evidence Supporting Nitrofurantoin for UTI

• Nitrofurantoin has demonstrated efficacy in treating uncomplicated UTIs with clinical and microbiological cure rates significantly higher than placebo 2
• The 5-day duration for nitrofurantoin is supported by multiple guidelines and has been shown to provide optimal balance between clinical efficacy and minimizing adverse effects 1
• Nitrofurantoin achieves adequate urinary concentrations and provides reliable activity against common UTI pathogens 1

Special Considerations

• Renal function: While some sources have historically cautioned against nitrofurantoin use in patients with reduced kidney function, evidence suggests it may still be effective in patients with mild to moderate reductions in estimated glomerular filtration rate 3
• Pregnancy: Nitrofurantoin is generally considered safe during pregnancy except in the last trimester 1
• Duration: While some international guidelines have suggested shorter courses (3 days), the strongest evidence supports a 5-day course for nitrofurantoin specifically 1, 4

Potential Adverse Effects

• Common adverse effects include gastrointestinal disturbances and skin rash 1
• Rare but serious adverse effects include pulmonary and hepatic toxicity (reported rates of 0.001% and 0.0003%, respectively) 1, 5
• Long-term prophylactic use may increase risk of adverse effects 6

Follow-Up Recommendations

• Routine post-treatment urinalysis or urine cultures are not indicated for asymptomatic patients 1
• If symptoms do not resolve by the end of treatment or recur within 2 weeks, a urine culture with antimicrobial susceptibility testing should be performed 1
• For recurrent UTIs (≥3 UTIs/year or ≥2 UTIs in 6 months), consider preventive strategies including non-antibiotic options 1

Alternative Treatments

• For patients who cannot tolerate nitrofurantoin, alternative options include:
  • Trimethoprim-sulfamethoxazole: 160/800 mg twice daily for 3 days 1
  • Cephalosporins (e.g., cefadroxil): 500 mg twice daily for 3 days (if local E. coli resistance is <20%) 1

Remember that the choice of antimicrobial should be guided by local resistance patterns, patient-specific factors, and previous culture results when available 1.