Does Macrobid (Nitrofurantoin) cause hyperglycemia in patients with Type 1 Diabetes Mellitus?

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: August 29, 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.

Macrobid (Nitrofurantoin) and Blood Sugar Effects in Type 1 Diabetes

There is no evidence that Macrobid (nitrofurantoin) causes elevated blood sugars in patients with Type 1 diabetes. The available guidelines and research do not indicate any direct hyperglycemic effect of nitrofurantoin in diabetic patients.

Medication Effects on Glycemic Control in Type 1 Diabetes

What We Know About Nitrofurantoin

  • Nitrofurantoin is commonly used to treat urinary tract infections in patients with diabetes
  • Unlike corticosteroids and some other medications, nitrofurantoin is not listed in any diabetes management guidelines as a medication that causes hyperglycemia 1
  • Research on nitrofurantoin use in diabetic patients has not demonstrated significant impacts on glycemic control 2

Medications Known to Affect Blood Glucose in Type 1 Diabetes

  • The American Diabetes Association guidelines identify several medications that can affect glycemic control, but nitrofurantoin is not among them 1
  • Medications known to cause hyperglycemia include:
    • Glucocorticoids (prednisone, dexamethasone)
    • Certain antipsychotics
    • Some immunosuppressants
    • Sympathomimetics

Monitoring Recommendations During Antibiotic Therapy

While nitrofurantoin itself is not known to cause hyperglycemia, patients with Type 1 diabetes should be aware that:

  • Infections themselves can cause hyperglycemia through stress response mechanisms 1
  • During any infection, including urinary tract infections, blood glucose monitoring should be increased due to the body's stress response 1
  • Illness-related stress can increase insulin requirements temporarily 3

Managing Type 1 Diabetes During Infection

If a patient with Type 1 diabetes is taking Macrobid for a urinary tract infection:

  • Continue regular insulin regimen but monitor blood glucose more frequently
  • Be prepared to adjust insulin doses upward temporarily to manage infection-related hyperglycemia 1
  • Maintain adequate hydration
  • Follow sick day management protocols as recommended by the American Diabetes Association 3

Important Considerations

  • If blood glucose levels rise after starting Macrobid, it is more likely due to the underlying infection rather than a direct effect of the medication
  • Patients should not discontinue Macrobid without consulting their healthcare provider, as untreated UTIs can lead to more serious complications
  • For patients with Type 1 diabetes, continuous glucose monitoring may be particularly helpful during periods of infection to detect patterns requiring insulin adjustment 1

In conclusion, while monitoring blood glucose is always important in Type 1 diabetes, especially during infection, there is no evidence that Macrobid itself causes hyperglycemia. Any elevated blood sugars observed while taking nitrofurantoin are more likely related to the body's stress response to the underlying infection rather than a direct medication effect.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Management of Type 1 Diabetes

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

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.