Nitrofurantoin Dosing in Pregnancy
For uncomplicated urinary tract infections in pregnant women, nitrofurantoin should be dosed at 100 mg orally twice daily (BID) for 5-7 days. 1
Standard Dosing Regimen
The recommended dose is nitrofurantoin monohydrate/macrocrystals 100 mg orally twice daily for 5-7 days for uncomplicated UTIs in pregnant women. 1, 2
This dosing regimen achieves clinical cure rates of 88-93% and bacterial cure rates of 81-92% in women with uncomplicated UTIs. 1
The 5-day regimen has been shown to be equivalent to trimethoprim-sulfamethoxazole in both clinical and microbiological cure rates. 1
Alternative Dosing for Specific Situations
For vancomycin-resistant Enterococci (VRE) uncomplicated UTIs, a higher dose of 100 mg orally four times daily (QID) may be used. 3, 1
An alternative formulation is nitrofurantoin macrocrystals at 50-100 mg orally four times daily for 5 days. 1
Safety and Efficacy in Pregnancy
Nitrofurantoin is considered safe for use during pregnancy and is included among first-line oral antibiotics for uncomplicated UTIs in pregnant women. 2
Single-dose fosfomycin (3 g) has been compared to nitrofurantoin (200 mg daily for one week) in pregnant women with bacteriuria, showing similar efficacy and safety profiles. 4, 5
A daily dose of nitrofurantoin combined with close surveillance significantly reduced asymptomatic bacteriuria in pregnant women with high clinic attendance rates (>90%). 6
Critical Contraindications
Nitrofurantoin is contraindicated in patients with creatinine clearance <60 mL/min due to inadequate urinary drug concentrations and increased risk of peripheral neuropathy and other toxicities. 7
Avoid nitrofurantoin if early pyelonephritis is suspected, as it does not achieve adequate tissue concentrations for upper tract infections. 1
Common Pitfalls to Avoid
Do not extend treatment beyond 7 days unless symptoms persist, as shorter courses minimize adverse effects while maintaining efficacy. 1
Nausea and headache are the most commonly reported side effects, with adverse event rates ranging from 5.6-34%. 1
Do not use nitrofurantoin for complicated UTIs or pyelonephritis—reserve it strictly for uncomplicated lower urinary tract infections. 3, 1