Is it safe to take magnesium and Macrobid (nitrofurantoin) together?

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Last updated: June 18, 2025View editorial policy

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From the Research

It's generally not recommended to take magnesium supplements at the same time as Macrobid (nitrofurantoin) as magnesium can interfere with the absorption of this antibiotic. If you need to take both medications, separate them by at least 2 hours. Macrobid is an antibiotic commonly used to treat urinary tract infections, while magnesium is a mineral supplement often taken for various health benefits. The concern is that magnesium can bind to nitrofurantoin in the digestive tract, forming complexes that reduce the antibiotic's absorption and effectiveness. This interaction is similar to how magnesium interacts with other medications like tetracyclines and fluoroquinolones. If you're currently taking Macrobid for an infection, it's essential to complete the full course as prescribed, even if symptoms improve before finishing. Some key points to consider when taking Macrobid include:

  • The effectiveness of nitrofurantoin in treating urinary tract infections, as shown in a study from 1
  • The potential for adverse reactions, such as pulmonary toxicity, as reported in 2
  • The importance of considering renal function when prescribing nitrofurantoin, as highlighted in 3
  • The use of nitrofurantoin prophylaxis in children with neurogenic bladder, as studied in 4
  • The comparison of 50 mg and 100 mg nitrofurantoin prophylaxis regimens, as investigated in 5 However, the most recent and highest quality study, 5, does not directly address the interaction between magnesium and Macrobid, but it does provide valuable information on the effectiveness and safety of nitrofurantoin prophylaxis. If you regularly take magnesium supplements, consult with your healthcare provider about the timing of your doses during antibiotic treatment to ensure you get the full benefit of both.

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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