What is Macrobid: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Dec 30, 2020

Macrobid overview

BRAND NAMES:

  • Nitrofurantoin Avpak, Macrobid

Generic Names:

  • Nitrofurantoin Monohyd Macro

Uses:

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

Therapeutic Classes:

  • Antibiotic

Forms:

  • Capsule

How it’s taken:

  • By mouth

What is Macrobid used for?

What form(s) does Macrobid come in

  • Capsule

What are common Macrobid doses?

  • Capsule 100MG

Common Macrobid prescriptions

  • Macrobid
    10 capsules bottle

  • Macrobid
    14 capsules bottle

  • Macrobid
    20 capsules bottle

  • Macrobid
    6 capsules bottle

  • Macrobid
    100mg capsule

How to take Macrobid

  • Take all of the medicine in your prescription to clear up your infection, even if you feel better after the first few doses.

  • Oral routeIt is best to take this medicine with food or milk.

  • Your doctor will tell you how much medicine to use. Do not use more than directed.

  • Take all of the medicine in your prescription to clear up your infection, even if you feel better after the first few doses.

  • Oral routeIt is best to take this medicine with food or milk.

  • Your doctor will tell you how much medicine to use. Do not use more than directed.

What to do if you miss a dose of Macrobid

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

  • 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.

  • Oral routeAsk your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.

Macrobid contraindications

  • 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.

Macrobid warnings

  • 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.

  • 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.

Macrobid interactions

  • 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.

  • Use this medicine only to treat the infection you now have. This medicine will not work for colds, flu, or other virus infections.

  • 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.

Macrobid side effects

Serious Side Effects

  • 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.

  • 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.

Less Serious Side Effects

  • Vaginal itching or fluids.

  • Dizziness, headache, or blurred vision.

  • Hair loss.

  • Mild nausea, vomiting, constipation, stomach upset, or pain.

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