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Nitrofurantoin combination (By mouth)

Nitrofurantoin Monohydrate (nye-troe-fure-AN-toyn mon-oh-HYE-drate), Nitrofurantoin, Macrocrystals (nye-troe-fure-AN-toyn MAK-roe-kris-tals)

Treats urinary tract infections caused by bacteria. This medicine is an antibiotic.

Brand Name(s):

Macrobid, Nitrofurantoin Avpak

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction to nitrofurantoin or if you are in your last weeks of pregnancy (week 38 or later). You should not use this medicine if you have severe kidney disease, if you are unable to urinate, or if you have a decreased amount of urine. Do not use this medicine if you have a history of liver disease with nitrofurantoin.

How to Use This Medicine:


  • Your doctor will tell you how much medicine to use. Do not use more than directed.
  • It is best to take this medicine with food or milk.
  • Take all of the medicine in your prescription to clear up your infection, even if you feel better after the first few doses.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are also using probenecid (Benemid®) or sulfinpyrazone (Anturane®).
  • It is best not to use antacids containing magnesium trisilicate (such as Foamicon® or Gaviscon®) while you are using nitrofurantoin.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have liver disease, heart disease, lung disease, anemia, diabetes, a mineral imbalance in the blood, or vitamin B deficiency. Make sure your doctor knows if you have a condition called G6PD-deficiency.
  • This medicine may cause your urine to be a brown color. This is normal and will not affect how the medicine works.
  • This medicine can cause diarrhea. Call your doctor if the diarrhea becomes severe, does not stop, or is bloody. Do not take any medicine to stop diarrhea until you have talked to your doctor. Diarrhea can occur 2 months or more after you stop taking this medicine.
  • Use this medicine only to treat the infection you now have. This medicine will not work for colds, flu, or other virus infections.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blisters, peeling, or red skin rash.
  • Cough, fever, chills, weakness, shortness of breath, or chest pain.
  • Dark-colored urine or pale stools.
  • Diarrhea or loose, watery stools that may contain blood.
  • Nausea, vomiting, loss of appetite, or pain in your upper stomach.
  • Numbness, tingling, or burning pain in your hands, arms, legs, or feet.
  • Yellowing of your skin or the whites of your eyes.

If you notice these less serious side effects, talk with your doctor:

  • Dizziness, headache, or blurred vision.
  • Hair loss.
  • Mild nausea, vomiting, constipation, stomach upset, or pain.
  • Vaginal itching or fluids.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 3/19/2020

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