Nitrofurantoin is used to treat urinary tract infections. This medicine is an antibiotic. It works by killing bacteria or preventing their growth. However, this medicine will not work for colds, flu, or other virus infections.

This medicine is available only with your doctor's prescription.

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

Nitrofurantoin is best taken with food or milk. This may lessen stomach upset and help your body to absorb the medicine.

To help clear up your infection completely, keep taking this medicine for the full time of treatment, even if you begin to feel better after a few days. Do not miss any doses.

Shake the oral liquid forcefully before each dose to make sure the medicine is evenly mixed. Use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

Swallow the capsule whole. Do not open, crush, or chew the capsule before swallowing it.

Do not take antacids containing magnesium trisilicate (e.g., Genaton®) while you are using nitrofurantoin. It may prevent the medicine from working properly.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Changes in facial skin color

chest pain

chills

cough

fever

general feeling of discomfort or illness

hives

hoarseness

itching

joint or muscle pain

shortness of breath

skin rash

sudden trouble in swallowing or breathing

swelling of the face, mouth, hands, or feet

troubled breathing

Less common

Black, tarry stools

blood in the urine or stools

burning, numbness, tingling, or painful sensations

dizziness

drowsiness

headache

pinpoint red spots on the skin

sore throat

unsteadiness or awkwardness

unusual bleeding or bruising

unusual tiredness or weakness

weakness in the arms, hands, legs, or feet

Rare

Abdominal or stomach pain

blindness

blistering, peeling, or loosening of the skin and mucous membranes

blue-yellow color blindness

bluish color of the fingernails, lips, skin, palms, or nail beds

blurred vision or loss of vision, with or without eye pain

bulging soft spot on the head of an infant

change in the ability to see colors, especially blue or yellow

confusion

cracks in the skin

darkening of the urine

decreased vision

diarrhea

diarrhea, watery and severe, which may also be bloody

eye pain

general tiredness and weakness

light-colored stools

loss of appetite

loss of heat from the body

mental depression

mood or mental changes

nausea or vomiting

pale skin

pale stools

red skin lesions, often with a purple center

red, irritated eyes

red, swollen skin

red, thickened, or scaly skin

skin rash

sores, ulcers, or white spots on the lips or in the mouth

swollen or painful glands

tenderness of salivary glands

unpleasant breath odor

upper right abdominal pain

visual changes

vomiting of blood

wheezing or tightness in the chest

yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Diarrhea

gas

Incidence not known

Dizziness or lightheadedness

feeling of constant movement of self or surroundings

lack or loss of strength

loss of hair, temporary

sensation of spinning

uncontrolled eye movements

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

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

If you or your child will be taking this medicine for a long time, it is very important that your doctor check you at regular visits for any problems or unwanted effects that may be caused by this medicine.

If you or your child's symptoms do not improve within a few days, or if they become worse, check with your doctor.

Diabetic patients that use urine sugar tests should be careful when using this medicine. Nitrofurantoin may cause false test results with some urine sugar tests. Check with your doctor before changing your diet or the dose of your diabetes medicine.

Liver problems may occur while you are using this medicine. Stop using this medicine and check with your doctor right away if you are having more than one of these symptoms: stomach pain or tenderness; clay-colored stools; dark urine; decreased appetite; fever; headache; itching; loss of appetite; nausea and vomiting; skin rash; swelling of the feet or lower legs; unusual tiredness or weakness; or yellow eyes or skin.

Tell your doctor right away if you start having numbness, tingling, or burning pain in your hands, arms, legs, or feet. These may be symptoms of a condition called peripheral neuropathy.

Nitrofurantoin may cause diarrhea, and in some cases it can be severe. Do not take any medicine to treat diarrhea without first checking with your doctor. Diarrhea medicines may make the diarrhea worse or make it last longer. If you have any questions about this, or if mild diarrhea continues or gets worse, check with your doctor.

This medicine may cause the urine to become a rust-yellow to brown color. This side effect does not require medical attention.