Nitrofurantoin

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Take this medication by mouth with food or milk as directed by your doctor. This medication is usually taken four times daily to treat an infection or once daily at bedtime to prevent infections. Swallow the medication whole. Avoid using magnesium trisilicate-containing antacids while taking this medication. Magnesium trisilicate-containing antacids bind with nitrofurantoin, preventing its full absorption.

The dosage and duration is based on your medical condition and response to treatment. Children's dosage is also based on weight.

For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day.

When taking this medication to prevent infection, take it exactly as directed by your doctor. Do not skip doses or stop taking it without your doctor's approval. Inform your doctor if you notice signs of a new urinary tract infection (such as pain while you are urinating).

If you are taking this medication to treat an infection, continue to take this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.

Tell your doctor if your condition lasts or gets worse.

Nausea, vomiting, loss of appetite, headache, or diarrhea may occur. Take this medication with food to help minimize nausea. If any of these effects last or get worse, notify your doctor or pharmacist promptly.

This medication may cause your urine to turn dark yellow or brown in color. This effect is harmless and will disappear when the medication is stopped.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

This medication may rarely cause very serious (possibly fatal) lung problems. Lung problems may occur within the first month of treatment or after long-term use of nitrofurantoin (generally for 6 months or longer). Get medical help right away if you develop symptoms of lung problems, including: cough that doesn't go away, chest pain, shortness of breath/trouble breathing, joint/muscle pain, bluish/purplish skin.

Tell your doctor right away if you have any serious side effects, including: headache that is severe or doesn't go away, new signs of infection (such as sore throat that doesn't go away, fever, chills), easy bruising/bleeding, mental/mood changes, vision changes.

This drug may rarely cause serious (possibly fatal) liver disease, blood or nerve problems. Tell your doctor right away if you notice any of the following serious side effects: nausea/vomiting that doesn't stop, unusual tiredness, dark urine, yellowing of eyes/skin, fast/pounding heartbeat, numbness/tingling of the arms/legs, muscle weakness.

This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: diarrhea that doesn't stop, abdominal or stomach pain/cramping, blood/mucus in your stool.

If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection (such as oral or vaginal fungal infection). Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

See also the How to Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

This medication may interfere with certain lab tests (such as certain urine glucose tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

Do not share this medication with others.

This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.

Lab and/or medical tests (such as complete blood counts, tests for kidney and liver function, urine cultures) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

Before taking nitrofurantoin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease (including liver problems caused by nitrofurantoin in the past), a certain genetic condition (G-6-PD deficiency), certain blood disorders (such as anemia), lung diseases, certain nerve problems (peripheral neuropathy), certain eye diseases (optic neuritis), diabetes, untreated mineral imbalance, vitamin B deficiency.

Nitrofurantoin may cause live bacterial vaccines (such as typhoid vaccine) to not work well. Tell your health care professional that you are using nitrofurantoin before having any immunizations/vaccinations.

Older adults may be at a greater risk for side effects while using this drug, especially nerve, liver or lung problems.

During pregnancy, this medication should be used only when clearly needed. This medication should not be used if you are near or at the time of delivery (weeks 38-42 of pregnancy) due to possible harm to the newborn, such as a certain blood problem (hemolytic anemia). Discuss the risks and benefits with your doctor.

This medication passes into breast milk and may have undesirable effects on nursing infants less than one month old and infants with a certain genetic condition (G-6-PD deficiency). Consult your doctor before breastfeeding.