Can I take Macrobid (nitrofurantoin) with Hyprex, and what are the potential interactions?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: June 12, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

You should not take Macrobid (nitrofurantoin) and Hyprex (methenamine hippurate) together as this combination is generally not recommended. Both medications are used to treat urinary tract infections but work through different mechanisms that can interfere with each other. Macrobid works by directly killing bacteria, while Hyprex requires an acidic urine environment to convert to formaldehyde, which is its active antibacterial form. The problem is that Macrobid can make your urine less acidic, which reduces Hyprex's effectiveness. Additionally, taking both medications simultaneously increases the risk of side effects affecting your urinary system, stomach, and liver without providing additional therapeutic benefit.

Key Points to Consider

  • The most recent guidelines from the European Association of Urology, as of 2024, suggest first-line treatments for uncomplicated cystitis that include fosfomycin trometamol, nitrofurantoin macrocrystals, and pivmecillinam 1.
  • Nitrofurantoin is recommended for the treatment of acute uncomplicated cystitis and pyelonephritis in women, with a dosage of 100 mg twice daily for 5 days, as per the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases guidelines from 2011 1.
  • There is no direct evidence in the provided studies regarding the interaction between Macrobid and Hyprex, but the mechanism of action and potential for reduced efficacy of Hyprex when urine acidity is altered suggests caution.
  • The decision to use one medication over the other should be based on the specific infection type, medical history, and other factors, as determined by a healthcare provider.

Recommendation

Based on the most recent and highest quality evidence, it is recommended to avoid taking Macrobid and Hyprex together. Instead, consult with a healthcare provider to determine the most appropriate treatment for your specific condition, considering factors such as the type of infection, medical history, and potential side effects. The provider may choose one medication based on these factors rather than recommending both simultaneously.

From the Research

Macrobid and Hyprex Interactions

  • There is no direct evidence in the provided studies regarding the interaction between Macrobid (nitrofurantoin) and Hyprex.
  • However, the studies provide information on the pharmacokinetics and potential interactions of nitrofurantoin with other drugs 2, 3, 4, 5.
  • Nitrofurantoin is commonly used to treat urinary tract infections and is excreted in the urine in high concentration 2.
  • The potential for drug-drug interactions (DDIs) is a concern when taking multiple medications, including Macrobid and Hyprex 6.
  • DDIs can occur through pharmacodynamic or pharmacokinetic interactions, and can be predicted using drug interaction software 6.
  • It is essential to consult with a healthcare professional or pharmacist to assess the potential risks and benefits of taking Macrobid and Hyprex together, as well as to monitor for any adverse effects 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.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.