What is the typical course of Macrobid (nitrofurantoin monohydrate) for an uncomplicated urinary tract infection (UTI)?

Macrobid Course for Uncomplicated UTI

For uncomplicated cystitis in women, prescribe nitrofurantoin monohydrate/macrocrystals (Macrobid) 100 mg twice daily for 5 days. 1, 2

Standard Dosing Regimen

• Nitrofurantoin monohydrate/macrocrystals (Macrobid): 100 mg orally twice daily for 5 days is the guideline-recommended first-line therapy for uncomplicated UTI in women 1, 2
• The 5-day regimen achieves clinical cure rates of 88-93% and bacterial cure rates of 81-92% 2
• This formulation allows twice-daily dosing due to its dual-release properties, improving compliance compared to older formulations requiring four-times-daily dosing 3

When to Extend Duration

• Consider 7 days of therapy if symptoms persist at day 5 or in specific clinical scenarios where treatment response may be slower 2, 4
• The American College of Physicians and IDSA guidelines support 5-7 day courses, with 5 days being optimal for most uncomplicated cases 1, 2

Special Dosing Situations

• For enterococcal UTIs (including VRE): Use 100 mg four times daily (every 6 hours) rather than twice daily 2, 3
• For men with uncomplicated UTI: Limited data support 7-14 days of therapy, though specific evidence is sparse 4
• For children ≥12 years: 100 mg twice daily; for children <12 years: 5-7 mg/kg/day divided into 4 doses (maximum 100 mg/dose) for 7 days 2

Critical Contraindications

• Do not use if creatinine clearance <60 mL/min 3
• Avoid if early pyelonephritis is suspected - nitrofurantoin does not achieve adequate tissue concentrations for upper tract infections 2
• Contraindicated in last trimester of pregnancy 3

Comparison to Alternative First-Line Agents

The 5-day nitrofurantoin regimen is equivalent in efficacy to:

• Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days (90% clinical cure for both) 2
• Ciprofloxacin 7-day regimens (95% cure rate), though fluoroquinolones should be reserved for more invasive infections 2, 4

Nitrofurantoin maintains a resistance rate of only 2.3% compared to 24% for fluoroquinolones and 29% for trimethoprim-sulfamethoxazole, making it an excellent fluoroquinolone-sparing option 5

Common Pitfalls to Avoid

• Do not prescribe for pyelonephritis or perinephric abscess - inadequate tissue penetration 2
• Do not extend beyond 7 days for uncomplicated cystitis unless symptoms persist, as longer courses increase adverse effects without improving efficacy 2
• Do not use in patients with renal impairment (CrCl <60 mL/min) due to risk of accumulation and serious adverse effects including pulmonary reactions and polyneuropathy 3
• Common side effects include nausea and headache (5.6-34% adverse event rate), which patients should be counseled about 2, 3

Follow-Up Recommendations

• Routine post-treatment urinalysis or urine cultures are not indicated for asymptomatic patients 2
• If symptoms do not resolve by end of treatment or recur within 2 weeks: Obtain urine culture with susceptibility testing and consider retreatment with a 7-day regimen using another agent 2