From the Guidelines
Nitrofurantoin is an effective antibiotic for treating urinary tract infections (UTIs), with common brand names including Macrobid, Macrodantin, and Furadantin. The medication comes in two main formulations: macrocrystalline (Macrodantin) and a combination of macrocrystalline and monohydrate forms (Macrobid) 1. Some key points to consider when prescribing nitrofurantoin include:
- The typical dosage is 100 mg capsules taken twice daily for 5-7 days for uncomplicated UTIs, or as 50-100 mg taken once daily for prophylaxis in patients with recurrent UTIs 1.
- Nitrofurantoin works by damaging bacterial DNA after being activated by bacterial enzymes, making it effective against many common urinary pathogens including E. coli 1.
- It should be taken with food to improve absorption and reduce gastrointestinal side effects.
- Patients should be aware that nitrofurantoin can turn urine brown or yellow and should complete the full course of treatment even if symptoms improve.
- Nitrofurantoin should be avoided in patients with significant kidney impairment (creatinine clearance <30 mL/min) as it may not reach effective concentrations in the urine and could increase toxicity risk 1. Some of the other options for treating UTIs include:
- Fosfomycin trometamol, which is recommended only in women with uncomplicated cystitis 1.
- Trimethoprim-sulfamethoxazole, which can be prescribed for 3 days in women with uncomplicated cystitis, but should be avoided in the last trimester of pregnancy 1.
- Pivmecillinam, which can be prescribed for 3-5 days in women with uncomplicated cystitis 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Nitrofurantoin Overview
- Nitrofurantoin is an antibiotic commonly used to treat urinary tract infections (UTIs) 2, 3, 4, 5, 6
- It is effective in preventing UTIs, with a risk ratio of 0.38 in favor of nitrofurantoin compared to no prophylaxis 4
- Nitrofurantoin has been used for over 60 years for UTI prevention and treatment 4
Efficacy and Safety
- Nitrofurantoin is effective in treating acute uncomplicated bacterial cystitis, with clinical cure rates ranging from 51 to 94% 6
- Bacteriological cure rates for nitrofurantoin range from 61 to 92% 6
- Nitrofurantoin is generally well-tolerated, with gastrointestinal and central nervous system symptoms being the most commonly reported side effects 5, 6
- Severe adverse effects are rare, with a frequency of 0.02-1.5 per 1000 nitrofurantoin users 4