By Medically reviewed by hellodoktor

Generic Name: Macrobid Brand Name(s): Generics only. No brands available.


What is Macrobid® (nitrofurantoin) used for?

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.

How should I take Macrobid® (nitrofurantoin)?

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 up to 3 days after lab tests show that the infection has cleared.

If you use this medicine long-term, 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®.

How do I store Macrobid® (nitrofurantoin)?

Macrobid® is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Macrobid® in the bathroom or the freezer. There may be different brands of Macrobid® that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Macrobid® down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Macrobid® (nitrofurantoin)?

Before using this drug, tell your doctor if:

  • You are pregnant or breastfeeding. This is because, while you are expecting or feeding a baby, you should only take medicines on the recommendation of a doctor.
  • You are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • You have allergy with any of active or inactive ingredients of Macrobid® or other medications.
  • You have any other illnesses, disorders, or medical conditions.

You should not take Macrobid® if you:

  • Have severe kidney disease.
  • Have a history of jaundice or liver problems caused by taking nitrofurantoin.
  • Are urinating less than usual or not at all.
  • 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
  • Any type of debilitating disease

Is it safe during pregnancy or breastfeeding?

There are no adequate studies in women for determining risk when using Macrobid® during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking Macrobid®. Macrobid® is pregnancy risk category B, according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk
  • B=No risk in some studies
  • C=There may be some risk
  • D=Positive evidence of risk
  • X=Contraindicated
  • N=Unknown

Side effects

What side effects can occur from Macrobid® (nitrofurantoin)?

Get emergency medical help if you have any of these signs of an allergic reaction to Macrobid®: hives; difficulty 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)
  • 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
  • Vaginal itching or discharge

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.


What drugs may interact with Macrobid® (nitrofurantoin)?

Macrobid® may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Macrobid® (nitrofurantoin)?

Macrobid® may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Macrobid® (nitrofurantoin)?

Macrobid® may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Health conditions that may interact with this drug are:

  • Kidney disease
  • Anemia
  • Diabetes
  • An electrolyte imbalance or vitamin B deficiency
  • Glucose-6-phosphate dehydrogenase (G6PD) deficiency
  • Any type of debilitating disease


The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using Macrobid® (nitrofurantoin).

What is the dose of Macrobid® (nitrofurantoin) for an adult?

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

What is the dose of Macrobid® (nitrofurantoin) for a child?

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

How is Macrobid® (nitrofurantoin) available?

Macrobid® is available in the following dosage forms and strengths:

  • Capsule: nitrofurantoin 25mg, nitrofurantoin monohydrate 75mg

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Macrobid®, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: August 7, 2017 | Last Modified: September 13, 2019

You might also like