SIDE EFFECTS: Nausea, vomiting, loss of appetite, or headache may occur. Take this medication with food to help minimize nausea. If any of these effects persist or worsen, 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 your doctor has prescribed this medication because he or she 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: persistent cough, chest pain, shortness of breath/trouble breathing, joint/muscle pain, bluish/purplish skin. Tell your doctor right away if any of these rare but very serious side effects occur: new signs of infection (e.g., fever, persistent sore throat), easy bruising/bleeding, mental/mood changes, persistent or severe headaches, 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 rare but very serious side effects: persistent nausea/vomiting, dark urine, yellowing of eyes/skin, unusual/persistent fatigue, fast/pounding heartbeat, numbness/tingling of the arms/legs, muscle weakness. This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Do not use anti-diarrhea or opioid medications if you have any of the following symptoms because these products may make them worse. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool. Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection (e.g., 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/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.

PRECAUTIONS: 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. This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: little or no urine output (oliguria or anuria), severe kidney disease, certain genetic conditions (glucose-6-phosphate dehydrogenase deficiency), a history of liver problems due to nitrofurantoin use in the past. Before using this medication, tell your doctor or pharmacist your medical history, especially of: certain blood disorders (e.g., anemia), kidney or liver problems, 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 as well. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to. Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, older adults may be at a greater risk for side effects while using this drug, especially nerve, liver or lung problems (see Side Effects section). This medication should be used only when clearly needed during pregnancy. This medication should not be taken if you are at term (weeks 38-42 of pregnancy), near or at the time of delivery 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 breast-feeding.

DRUG INTERACTIONS: See also the How to Use section. Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop or change the dosage of any medicine before checking with them first. Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: sulfinpyrazone. Although most antibiotics are unlikely to affect hormonal birth control such as pills, patch, or ring, a few antibiotics (such as rifampin, rifabutin) can decrease their effectiveness. This could result in pregnancy. If you use hormonal birth control, ask your doctor or pharmacist for more details. This drug can affect the results of certain urine glucose tests (cupric sulfate-type). Make sure laboratory personnel and your doctors know you use this drug. This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

OVERDOSE: 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.