Description and Brand Names

Drug information provided by: Merative, Micromedex®

US Brand Name

  1. Furadantin
  2. Macrodantin

Canadian Brand Name

  1. Novo-Furan Suspension

Descriptions


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.

This product is available in the following dosage forms:

  • Suspension
  • Capsule

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of nitrofurantoin in children. Safety and efficacy have not been established in infants below 1 month of age.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of nitrofurantoin in the elderly. However, elderly patients are more likely to have age-related heart, liver, lung, or kidney problems, which may require caution in patients receiving nitrofurantoin.

Breastfeeding

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Cholera Vaccine, Live
  • Fluconazole
  • Levoketoconazole
  • Methotrexate

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Anemia or
  • Diabetes mellitus or
  • Mineral imbalance in the blood or
  • Vitamin B deficiency—May increase the chance for side effects.
  • Diarrhea or
  • Liver disease or
  • Lung disease—Use with caution. May make these conditions worse.
  • Glucose-6-phosphate dehydrogenase (G6PD) deficiency (an enzyme problem in red blood cells)—May cause hemolytic anemia (red blood cells are destroyed) in patients with this condition.
  • Kidney disease (not infection)—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
  • Kidney disease, severe or
  • Liver disease, history of with this medicine, or
  • Urinating problems (e.g., unable to urinate or decreased amount of urine)—Should not be used in patients with these conditions.

Proper Use

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.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage forms (capsules, suspension, and tablets):
    • For prevention of urinary tract infections:
      • Adults and teenagers—50 to 100 milligrams (mg) at bedtime.
      • Children and infants 1 month of age and older—Dose is based on body weight and must be determined by your doctor.
      • Infants younger than 1 month of age—Use is not recommended.
    • For treatment of urinary tract infections:
      • Adults and teenagers—50 to 100 milligrams (mg) every six hours.
      • Children and infants 1 month of age and older—Dose is based on body weight and must be determined by your doctor.
      • Infants younger than 1 month of age—Use is not recommended.
  • For oral dosage form (extended-release capsules):
    • For treatment of urinary tract infections:
      • Adults, teenagers, and children 12 years of age and older—100 milligrams (mg) every twelve hours for seven days.
      • Children younger than 12 years of age—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions

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.

Side Effects

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

  1. Changes in facial skin color
  2. chest pain
  3. chills
  4. cough
  5. fever
  6. general feeling of discomfort or illness
  7. hives
  8. hoarseness
  9. itching
  10. joint or muscle pain
  11. shortness of breath
  12. skin rash
  13. sudden trouble in swallowing or breathing
  14. swelling of the face, mouth, hands, or feet
  15. troubled breathing

Less common

  1. Black, tarry stools
  2. blood in the urine or stools
  3. burning, numbness, tingling, or painful sensations
  4. dizziness
  5. drowsiness
  6. headache
  7. pinpoint red spots on the skin
  8. sore throat
  9. unsteadiness or awkwardness
  10. unusual bleeding or bruising
  11. unusual tiredness or weakness
  12. weakness in the arms, hands, legs, or feet

Rare

  1. Abdominal or stomach pain
  2. blindness
  3. blistering, peeling, or loosening of the skin and mucous membranes
  4. blue-yellow color blindness
  5. bluish color of the fingernails, lips, skin, palms, or nail beds
  6. blurred vision or loss of vision, with or without eye pain
  7. bulging soft spot on the head of an infant
  8. change in the ability to see colors, especially blue or yellow
  9. confusion
  10. cracks in the skin
  11. darkening of the urine
  12. decreased vision
  13. diarrhea
  14. diarrhea, watery and severe, which may also be bloody
  15. eye pain
  16. general tiredness and weakness
  17. light-colored stools
  18. loss of appetite
  19. loss of heat from the body
  20. mental depression
  21. mood or mental changes
  22. nausea or vomiting
  23. pale skin
  24. pale stools
  25. red skin lesions, often with a purple center
  26. red, irritated eyes
  27. red, swollen skin
  28. red, thickened, or scaly skin
  29. skin rash
  30. sores, ulcers, or white spots on the lips or in the mouth
  31. swollen or painful glands
  32. tenderness of salivary glands
  33. unpleasant breath odor
  34. upper right abdominal pain
  35. visual changes
  36. vomiting of blood
  37. wheezing or tightness in the chest
  38. 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

  1. Diarrhea
  2. gas

Incidence not known

  1. Dizziness or lightheadedness
  2. feeling of constant movement of self or surroundings
  3. lack or loss of strength
  4. loss of hair, temporary
  5. sensation of spinning
  6. 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.

Portions of this document last updated: Nov. 01, 2023

Original article: https://www.mayoclinic.org/drugs-supplements/nitrofurantoin-oral-route/precautions/drg-20065102