Nitrofurantoin

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

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 cause your urine to turn dark yellow or brown in color. This is usually a harmless, temporary effect and will disappear when the medication is stopped. However, dark brown urine can also be a sign of rare side effects (liver problems or anemia). Get medical help right away if you notice dark urine along with any of the following symptoms: nausea/vomiting that doesn't stop, stomach/abdominal pain, yellowing eyes/skin, tiredness, fast/pounding heartbeat.

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

Get medical help right away if you have any very serious side effects, including: numbness/tingling of the hands/feet, unusual muscle weakness.

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.

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 nitrofurantoin for prolonged or repeated periods may result in oral thrush or a new vaginal yeast 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/medwatch.

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

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), lung disease, numbness/tingling of the arms/legs, vitamin B deficiency, mineral imbalance, blood disorders (such as anemia), diabetes, ongoing weakness due to long-term disease, certain eye disorders (such as optic neuritis).

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

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

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.

During pregnancy, this medication should be used only when clearly needed. It must not be used if you are near the end of your pregnancy (38-42 weeks) or at the time of labor and delivery. Doing so may cause a certain blood disorder (hemolytic anemia) in your baby. Discuss the risks and benefits with your doctor.

This medication passes into breast milk and may have undesirable effects on nursing infants younger than 1 month old or those with a certain genetic condition (G-6-PD deficiency). Consult your doctor before breastfeeding.

See also 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.

Some products that may interact with this drug are: certain drugs to treat gout (uricosuric drugs such as sulfinpyrazone).

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.

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 their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

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 kidney/liver function, blood counts/CBC, bacterial culture) should be done while you are taking this medication. Lung function tests should be performed if you are prescribed nitrofurantoin products for extended treatment (several months or more). Keep all medical and lab appointments. Consult your doctor for more details.

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.

Store at room temperature. Protect from light and from freezing. Discard any unused medication 30 days after opening the bottle. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.