Is Macrobid (Nitrofurantoin) an antibiotic?

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Last updated: February 15, 2025View editorial policy

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From the Guidelines

Yes, Macrobid (Nitrofurantoin) is an antibiotic.

Overview of Nitrofurantoin

  • Nitrofurantoin is commonly used to treat urinary tract infections (UTIs) [ 1 ].
  • It is a first-line agent for re-treatment of UTIs due to its low resistance rates [ 1 ].

Usage and Recommendations

  • The American College of Physicians recommends prescribing short-course antibiotics, including nitrofurantoin, for uncomplicated cystitis [ 1 ].
  • Nitrofurantoin is typically prescribed for 5 days for uncomplicated bacterial cystitis [ 1 ].
  • It is also used for prophylaxis in children with vesicoureteral reflux (VUR) to prevent recurrent febrile UTIs [ 1 ].

Important Considerations

  • Nitrofurantoin should be avoided in infants under 4 months due to the risk of hemolytic anemia [ 1 ].
  • Local antimicrobial susceptibility patterns should be considered when selecting empirical antimicrobial therapy [ 1 ].

From the FDA Drug Label

Clostridium difficile-associated diarrhea: Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including nitrofurantoin, and may range in severity from mild diarrhea to fatal colitis.

  • Macrobid (Nitrofurantoin) is an antibiotic because it is included in the list of antibacterial agents that can cause Clostridium difficile-associated diarrhea (CDAD) 2.

From the Research

Definition and Classification of Macrobid (Nitrofurantoin)

  • Macrobid, also known as Nitrofurantoin, is classified as an antibiotic 3, 4, 5, 6, 7.
  • It is a broad-spectrum bactericidal antibiotic that is effective against a wide range of gram-positive and gram-negative bacteria 4, 5.

Mechanism of Action

  • Nitrofurantoin works by interfering with the synthesis of cell wall, bacterial proteins, and DNA of both gram-positive and gram-negative pathogens 4.
  • It is converted to highly reactive electrophilic intermediates by bacterial nitroreductases, which attack bacterial ribosomal proteins non-specifically, causing complete inhibition of protein synthesis 7.

Clinical Use

  • Nitrofurantoin is primarily used as an oral antibacterial treatment for genitourinary infections, including urinary tract infections (UTIs) 3, 5, 6.
  • It is recommended as a first-line antibiotic for the empiric treatment of uncomplicated cystitis in otherwise healthy women 3.
  • Nitrofurantoin has also been used for the prophylaxis of recurrent uncomplicated UTIs 3, 5.

Resistance and Efficacy

  • Despite its long application, nitrofurantoin has retained good activity against common urinary tract pathogens, including Escherichia coli and Staphylococcus saprophyticus 3.
  • The lack of clinically significant bacterial resistance development to nitrofurantoin is likely due to its multiple sites of attack and multiple mechanisms of action 7.
  • Recent studies have shown that nitrofurantoin has a good efficacy and tolerability profile, comparable to other standard therapeutic regimens 3, 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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