What is Nitrofurantoin: Uses, Warnings & Interactions

Your healthcare provider will tell you how much medicine to use. Do not use more than directed.

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

Nitrofurantoin doses should be taken with food.

How to take nitrofurantoin capsules:

• Swallow the capsule whole with a drink of water.

• Store nitrofurantoin capsules at room temperature in a tightly closed, light-resistant container.

How to take nitrofurantoin oral suspension:

• Shake the bottle well before measuring a dose.

• Use only the calibrated oral syringe that comes with this medicine to measure out a dose. If it’s missing, the pharmacist can provide one for free.

• Store nitrofurantoin oral suspension at room temperature in its original bottle. Do not freeze.

• The oral suspension is good for 30 days. Throw out any unused medicine after 30 days.

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.

You should not use this medicine if you have had an allergic reaction to nitrofurantoin.

Nitrofurantoin should never be administered to women during:

• The last few weeks of pregnancy (week 38 or later)

• The onset of labor

• Labor

• Delivery

Nitrofurantoin is also contraindicated in people with:

• Severe kidney disease

• Decreased urine

• Inability to urinate

• A history of liver problems when taking nitrofurantoin

Nitrofurantoin cannot be safely used in infants younger than 1 month old.

Tell any healthcare provider who treats you that you are using this medicine.

Your healthcare provider may need to perform lab tests regularly to monitor the infection and the effects of this medicine, particularly if it’s been taken long-term to suppress UTIs. Keep all appointments.

It is not safe to take this medicine during late-term pregnancy (weeks 38–42). Tell the healthcare provider if you are pregnant and at what stage.

Tell the healthcare provider if you have:

• Kidney disease

• A rare genetic blood disorder called G6PD deficiency

Nitrofurantoin can cause serious adverse effects, including:

• Severe lung disease

• Nerve damage in the extremities (peripheral neuropathy)

• Red blood cell death (hemolytic anemia)

• Other types of anemia

Nitrofurantoin can cause serious and potentially fatal lung reactions, including chronic interstitial pneumonitis or pulmonary fibrosis. The drug must be immediately discontinued at any sign of lung problems (see side effects below).

This medicine can cause severe diarrhea, which may occur several weeks or months after treatment ends. Call your doctor if you experience severe, watery, persistent, or bloody diarrhea. Do not take any medicine to treat the diarrhea until you have talked to a healthcare provider. 

This medicine may cause your urine to become brown-colored. This is normal and is not health-threatening unless you experience other symptoms (see side effects below).

To avoid potentially hazardous drug interactions, tell the prescribing healthcare provider about all prescription drugs, over-the-counter medications, and supplements you use before taking nitrofurantoin, particularly the gout treatments sulfinpyrazone or probenecid.

Tell other healthcare providers you are taking nitrofurantoin. Nitrofurantoin may alter urine glucose tests.

Do not use antacids that contain magnesium trisilicate when taking nitrofurantoin. You can use other antacids, but make sure to take the nitrofurantoin dose at least one hour before or one hour after taking the antacid.