Generic name: nitrofurantoin [ NYE-troe-fue-RAN-toin ]
Drug class: Urinary anti-infectives

Medically reviewed by Sanjai Sinha, MD. Last updated on Aug 26, 2024.

What is Macrobid?

Macrobid is an antibiotic that fights bacteria in the body.

Macrobid is used to treat urinary tract infections.

Macrobid may also be used for purposes not listed in this medication guide.

Warnings

You should not take Macrobid if you have severe kidney disease, complicated urinary tract infection, or a history of jaundice or liver problems caused by nitrofurantoin.

Do not take Macrobid if you are in the last 2 to 4 weeks of pregnancy.

Before taking this medicine

You should not take Macrobid if you are allergic to nitrofurantoin, or if you have:

• severe kidney disease;

• a history of jaundice or liver problems caused by taking nitrofurantoin;

• if you are urinating less than usual or not at all; or

• if you are in the last 2 to 4 weeks of pregnancy.

Do not take Macrobid if you are in the last 2 to 4 weeks of pregnancy.

To make sure Macrobid is safe for you, tell your doctor if you have:

• kidney disease;

• anemia;

• diabetes;

• an electrolyte imbalance or vitamin B deficiency;

• glucose-6-phosphate dehydrogenase (G6PD) deficiency; or

• any type of debilitating disease.

FDA pregnancy category B. Macrobid is not expected to be harmful to an unborn baby during early pregnancy. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Nitrofurantoin can pass into breast milk and may harm a nursing baby. You should not breast-feed while you are taking Macrobid.

Macrobid should not be given to a child younger than 1 month old.

How should I take Macrobid?

Take Macrobid exactly as prescribed by your doctor. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Take Macrobid with food.

Shake the oral suspension (liquid) well just before you measure a dose. Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

You may mix your liquid dose with water, milk, or fruit juice to make it easier to swallow. Drink the entire mixture right away.

Use this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Macrobid will not treat a viral infection such as the common cold or flu.

Macrobid is usually given for 5 days in females and 7 days in males for uncomplicated UTI.

If you use this medicine long-term, for prevention of UTI, you may need frequent medical tests at your doctor's office.

Macrobid can cause unusual results with certain lab tests for glucose (sugar) in the urine. Tell any doctor who treats you that you are using Macrobid.

Store at room temperature away from moisture, heat, and light.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What to avoid

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or has blood in it, call your doctor. Do not use any medicine to stop the diarrhea unless your doctor has told you to.

Avoid using antacids without your doctor's advice. Use only the type of antacid your doctor recommends. Some antacids can make it harder for your body to absorb nitrofurantoin.

Macrobid side effects

Get emergency medical help if you have any of these signs of an allergic reaction to Macrobid: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• diarrhea that is watery or bloody;

• sudden chest pain or discomfort, wheezing, dry cough or hack;

• new or worsening cough, trouble breathing;

• fever, chills, body aches, tiredness, unexplained weight loss;

• numbness, tingling, or pain in your hands or feet;

• liver problems--nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

• lupus-like syndrome--joint pain or swelling with fever, swollen glands, muscle aches, chest pain, vomiting, unusual thoughts or behavior, and patchy skin color.

Serious side effects may be more likely in older adults and those who are ill or debilitated.

Common Macrobid side effects may include:

• headache, dizziness;

• gas, upset stomach;

• mild diarrhea; or

• vaginal itching or discharge.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Dosing information

Usual Adult Dose for Cystitis:

Regular release: 50 to 100 mg orally 4 times a day for 1 week or for at least 3 days after urine sterility is obtained
Dual release: 100 mg orally twice a day for 7 days

Usual Adult Dose for Cystitis Prophylaxis:

Regular release: 50 to 100 mg orally once a day at bedtime

Usual Pediatric Dose for Cystitis:

Regular release:
1 month or older: 5 to 7 mg/kg/day (up to 400 mg/day) orally in 4 divided doses

Dual release:
Greater than 12 years: 100 mg orally twice a day for 7 days

Usual Pediatric Dose for Cystitis Prophylaxis:

Regular release:
1 month or older: 1 to 2 mg/kg/day (up to 100 mg/day) orally in 1 to 2 divided doses

Related/similar drugs

amoxicillin, doxycycline, ciprofloxacin, cephalexin, ceftriaxone, Augmentin, levofloxacin, nitrofurantoin, Bactrim, Keflex

What other drugs will affect Macrobid?

Other drugs may interact with nitrofurantoin, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Frequently asked questions

• What is "dual release" nitrofurantoin?
• Is meloxicam a sulfa drug?
• Does Macrobid make birth control pills less effective?
• What antibiotics are used to treat UTI?

View more FAQ

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Macrobid only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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