What is the recommended dosage of Macrobid (Nitrofurantoin) for pregnant women with urinary tract infections?

Nitrofurantoin (Macrobid) Dosage for Pregnant Women with UTIs

The recommended dosage of Macrobid (nitrofurantoin) for pregnant women with urinary tract infections is 100 mg orally twice daily for 5-7 days. 1

First-Line Treatment Options for UTIs in Pregnancy

Nitrofurantoin is one of the safest and most effective first-line treatments for UTIs during pregnancy, as recommended by the American College of Obstetricians and Gynecologists 1. The other recommended options include:

• Cephalexin
• Fosfomycin

Nitrofurantoin Dosing Details

• Standard therapeutic dose: 100 mg twice daily 1, 2
• Duration: 5-7 days for symptomatic UTIs 1, 2
• Prophylactic dose: 50 mg as a single post-coital dose (for women with history of recurrent UTIs) 3

Safety Considerations in Pregnancy

• Nitrofurantoin is generally safe throughout most of pregnancy 1
• Important caution: Avoid use during the last trimester due to potential risk of hemolytic anemia in the newborn 1
• Reaches high bactericidal concentrations in the urinary tract with minimal development of bacterial resistance 3

Treatment Algorithm for UTIs in Pregnancy

1. For asymptomatic bacteriuria:

   • Treatment is essential in pregnancy (reduces risk of pyelonephritis and preterm delivery) 4
   • Single-dose therapy may be less effective than multi-day regimens 4
   • Recommended: 5-7 day course rather than single-dose treatment 4

2. For symptomatic UTI:

   • Nitrofurantoin 100 mg twice daily for 5-7 days 1, 2
   • Alternative: Cephalexin 500 mg four times daily for 5-7 days 1
   • Alternative: Fosfomycin 3g single dose 1

3. For recurrent UTIs during pregnancy:

   • Consider prophylactic therapy with nitrofurantoin 50 mg as a single post-coital dose 3
   • This approach has been shown to significantly reduce recurrence rates 3

Follow-up and Monitoring

• Repeat urine culture 1-2 weeks after completing treatment 1
• Monitor for symptom resolution within 48-72 hours 1
• If symptoms persist or worsen, reevaluate with imaging to rule out complications 1

Medications to Avoid During Pregnancy

• Trimethoprim-sulfamethoxazole: Avoid in first and third trimesters due to risk of neural tube defects and kernicterus 1
• Tetracyclines: Contraindicated throughout pregnancy 1
• Fluoroquinolones: Should be reserved for more invasive infections and generally avoided in pregnancy 2

Clinical Pearls

• UTI treatment in pregnancy is essential even when asymptomatic to prevent complications including pyelonephritis and preterm delivery
• For women with history of recurrent UTIs, post-coital prophylaxis with nitrofurantoin 50 mg has shown excellent results 3
• The standard 5-7 day treatment course is preferred over single-dose therapy during pregnancy 4
• Always obtain a follow-up urine culture after treatment to ensure cure 1

For pregnant women with UTIs requiring hospitalization, transfer to a tertiary center with access to both gastroenterology and high-risk obstetrics is recommended for optimal care 5.