What is the difference between Nitrofurantoin and Macrobid (Nitrofurantoin)?

Nitrofurantoin vs. Macrobid: Understanding the Difference

Macrobid is a brand name for nitrofurantoin monohydrate/macrocrystals, which is a specific formulation of nitrofurantoin. 1, 2

Formulation Differences

• Nitrofurantoin is available in different formulations: macrocrystals (Macrodantin), monohydrate, and monohydrate/macrocrystals (Macrobid) 1
• Macrobid specifically contains the monohydrate/macrocrystals formulation of nitrofurantoin, which provides both immediate and sustained release of the medication 1, 3
• The macrocrystal formulation allows for better absorption and potentially fewer gastrointestinal side effects compared to older nitrofurantoin formulations 4

Dosing Considerations

• Macrobid (nitrofurantoin monohydrate/macrocrystals) is typically dosed at 100 mg twice daily for 5-7 days for uncomplicated UTIs 1
• Other nitrofurantoin formulations may have different dosing regimens:
  • Nitrofurantoin macrocrystals can be dosed at 50-100 mg four times daily for 5 days 1
  • Nitrofurantoin macrocrystals prolonged release can be dosed at 100 mg twice daily for 5 days 1

Clinical Applications

• Both Macrobid and other nitrofurantoin formulations are recommended as first-line treatments for uncomplicated urinary tract infections by major guidelines 1, 3
• Clinical cure rates with nitrofurantoin (including Macrobid) range from 88-93% for uncomplicated UTIs 1
• Bacterial cure rates range from 81-92% for uncomplicated UTIs 1

Antimicrobial Properties

• All nitrofurantoin formulations, including Macrobid, are broad-spectrum antibiotics effective against many gram-positive and gram-negative urinary pathogens 4, 5
• Nitrofurantoin has multiple mechanisms of action that may help prevent the development of resistance, which is why it has maintained effectiveness despite decades of use 6
• Both formulations are particularly valuable in the era of increasing antimicrobial resistance 4, 5

Important Precautions

• All nitrofurantoin formulations, including Macrobid, are contraindicated in patients with creatinine clearance <60 mL/min due to inadequate urinary drug concentrations and increased risk of toxicity 3
• Both can cause acute pulmonary reactions ranging from mild dyspnea to noncardiogenic pulmonary edema in some patients 7
• Common side effects for all nitrofurantoin formulations include nausea and headache 1

Clinical Decision Making

• When prescribing for uncomplicated UTIs, Macrobid (nitrofurantoin monohydrate/macrocrystals) at 100 mg twice daily for 5 days is the preferred formulation according to the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases 1, 3
• For patients who cannot tolerate twice-daily dosing or who might benefit from a different release profile, other nitrofurantoin formulations may be considered 1

In summary, the main difference is that Macrobid is a specific brand name for the nitrofurantoin monohydrate/macrocrystals formulation, which offers a dual-release mechanism that may provide advantages in terms of dosing convenience and tolerability compared to other nitrofurantoin formulations.