Nitrofurantoin

Reviewed on 10/18/2021

What Is Nitrofurantoin and How Does It Work?

Nitrofurantoin is a prescription medication used to treat the symptoms of urinary tract infection (UTI) caused by bacteria such as Escherichia coli, Enterobacter spp, Klebsiella spp, Staphylococcus aureus, and S. saprophyticus.

Nitrofurantoin is available under the following different brand names: Macrobid, Macrodantin, Furadantin.  

What Are Dosages of Nitrofurantoin?

Adult dosage

Capsule, macrocrystals

  • 25mg
  • 50mg
  • 100mg
  • 50-100mg orally every 6 hours for 7 days or for 3 days after obtaining sterile urine

Capsule, monohydrate/macrocrystals

  • 100mg
  • 100mg orally every 12 hour for 7 days or for 3 days after obtaining sterile urine 

Oral suspension

  • 25mg/5mL
  • Longer-term prophylaxis/suppression: 50-100 mg macrocrystals orally at bedtime for up to 12 months. 

Pediatric dosage

Capsule, macrocrystals

  • 25mg
  • 50mg
  • 100mg

Capsule, monohydrate/macrocrystals

  • 100mg

Oral suspension

  • 25mg/5mL 
  • Children older than 1 month of age: 5-7 mg/kg/day orally divided every 6 hours for 7 days
  • UTI prophylaxis: 1-2 mg/kg orally at bedtime or 2 divided doses
  • Macrocrystals (Macrodantin, Furadantin, and equivalents): children older than 12 years of age: 50-100mg orally every 6 hours for 7 days or for 3 days after obtaining sterile urine
  • Monohydrate/macrocrystals (Macrobid and equivalents): children older than 12 years of age: 100 mg orally every 12 hours for 7 days or for 3 days after obtaining sterile urine
  • Long-term prophylaxis/suppression: children older than 12 years of age: 50-100 mg macrocrystals orally at bedtime for up to 12 months. 

Dosage Considerations – Should be Given as Follows: 

  • Avoid for long-term UTI suppression; possible pulmonary toxicity; safer alternatives are available
  • Loses effectiveness in patients with creatinine clearance (CrCl) less than 60 mL/min due to inadequate urine concentration (Beers criteria)
  • Monitor renal function; renally excreted; decreased renal function more likely in elderly
  • Monitor liver function
  • Take with food or milk
  • Dual release macrocrystals indicated only for patients older than 12 years of age for acute UTIs (cystitis) caused by E coli or S saprophyticus

SLIDESHOW

Urinary Incontinence in Women: Types, Causes, and Treatments for Bladder Control See Slideshow

What Are Side Effects Associated with Using Nitrofurantoin?

Common side effects of Nitrofurantoin include:

  • headache, 
  • dizziness, 
  • drowsiness, 
  • weakness, 
  • gas, 
  • indigestion
  • loss of appetite, 
  • nausea, 
  • vomiting, 
  • muscle or joint pain, 
  • rash, 
  • itching, and
  • temporary hair loss

Serious side effects of Nitrofurantoin include:

  • hives, 
  • difficulty breathing, 
  • swelling in face or throat, 
  • fever, 
  • sore throat
  • burning eyes, 
  • skin pain, 
  • red or purple skin rash with blistering and peeling, 
  • severe stomach pain, 
  • diarrhea that is watery or bloody (even if it occurs months after your last dose), 
  • vision problems, 
  • fever, 
  • chills, 
  • cough, 
  • chest pain, 
  • numbness, tingling, or burning in hands or feet, 
  • severe pain behind eyes, 
  • pale skin, 
  • weakness, 
  • joint pain or swelling with fever, 
  • swollen glands, 
  • muscle aches, 
  • pain, redness, or swelling in the lower jaw, 
  • severe headaches, 
  • ringing in ears, 
  • dizziness, 
  • nausea, 
  • vision problems, 
  • upper stomach pain (that may spread to the back), 
  • vomiting, 
  • dark urine, and
  • yellowing of the skin or eyes 

Rare side effects of Nitrofurantoin include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Nitrofurantoin?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them.  Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first

  • Nitrofurantoin has no known severe interactions with other drugs
  • Nitrofurantoin has serious interactions with the following other drugs:
  • Nitrofurantoin has moderate interactions with at least 35 other drugs  
  • Nitrofurantoin has mild interactions with at least 13 other drugs
 

This information does not contain all possible interactions or adverse effects.  Visit the RxList Drug Interaction Checker for any drugs 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 this information with your doctor and pharmacist.  Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

What Are Warnings and Precautions for Nitrofurantoin?

Keep out of reach of children.  In case of overdose, get medical help or contact a Poison Control Center immediately

Contraindications

  • Hypersensitivity to IV components, beta-lactams, or other drugs in this class
  • Renal failure (anuria, oliguria, or CrCl less than 60 mL/min)
  • Pregnancy at term (38-42 weeks of gestation)
  • History of hepatic dysfunction/cholestatic jaundice with nitrofurantoin
  • Neonates (younger than 28 days)
  • Hypersensitivity

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Nitrofurantoin?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Nitrofurantoin?”

Cautions

  • Caution in patients with G6PD deficiency (may increase risk for hemolytic anemia)
  • Avoid long-term use in the elderly (may increase risk for pulmonary toxicity)
  • Renal impairment
  • Discontinue if paresthesia or hemolysis develop
  • Risk of occasional hepatotoxicity and pulmonary toxicity
  • Protect from light
  • Peripheral neuropathy may occur; risk may increase in patients diagnosed with anemia, diabetes, vitamin B deficiency, or electrolyte imbalance (use caution)
  • Acute/chronic pulmonary reactions (eg., cough, interstitial pneumonitis or fibrosis) reported
  • Bacterial superinfections may occur with prolonged treatment

Pregnancy and Lactation

  • Use in pregnancy is contraindicated at term.  Use may be acceptable during pregnancy.  Medication crosses the placenta but is not well distributed. 
  • Nitrofurantoin enters breast milk; discontinue drug or do not nurse.

QUESTION

How much urine does the average adult pass each day? See Answer
References
https://reference.medscape.com/drug/macrobid-macrodantin-nitrofurantoin-342567

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