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a broad-spectrum antibacterial agent used in treatment of urinary tract infections.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


Apo-Nitrofurantoin, Furadantin, Novo-Furantoin

nitrofurantoin macrocrystals

Macrobid, Macrodantin

Pharmacologic class: 5-nitrofuran derivative

Therapeutic class: Anti-infective, urinary tract anti-infective

Pregnancy risk category B


Inhibits bacterial enzymes required for normal cell activity at low concentrations; inhibits normal cell-wall synthesis at high concentrations


Capsules: 25 mg, 50 mg, 100 mg (macrocrystals)

Capsules (extended-release): 100 mg (macrocrystals)

Oral suspension: 25 mg/5 ml

Tablets: 50 mg, 100 mg (macrocrystals)

Indications and dosages

Active urinary tract infections (UTIs)

Adults: 50 to 100 mg P.O. q.i.d. or 100 mg q 12 hours (extended-release), continued for 1 week, or for 3 days after urine becomes sterile

Children older than 1 month: 5 to 7 mg/kg/day P.O. in four divided doses, continued for 1 week, or for 3 days after urine becomes sterile

Chronic suppression of UTIs

Adults: 50 to 100 mg P.O. at bedtime

Children: 1 mg/kg/day P.O. in one or two divided doses


• Hypersensitivity to drug or parabens (oral suspension)

• Oliguria, anuria, or significant renal impairment

• Pregnancy near term (38 to 42 weeks' gestation), imminent labor onset, labor and delivery

• Infants younger than 1 month


Use cautiously in:

• diabetes mellitus, renal impairment

• blacks and patients of Mediterranean or near-Eastern descent (because of possible G6PD deficiency)

• elderly or debilitated patients

• pregnant (to week 32) or breastfeeding patients.


• As appropriate, obtain specimens for repeat urine culture and sensitivity tests before therapy.

• To avoid GI upset and increase drug bioavailability, give with food or milk.

Adverse reactions

CNS: dizziness, drowsiness, headache, asthenia, peripheral neuropathy, vertigo

CV: chest pain

EENT: nystagmus

GI: nausea, vomiting, diarrhea, abdominal pain, anorexia, parotitis, pancreatitis

Hematologic: eosinophilia, agranulocytosis, thrombocytopenia, leukopenia, granulocytopenia, G6PD deficiency anemia, hemolytic anemia, megaloblastic anemia

Hepatic: hepatitis, hepatic necrosis

Musculoskeletal: arthralgia, myalgia

Respiratory: asthma attacks, pulmonary hypersensitivity reactions including diffuse interstitial pneumonias (with prolonged therapy)

Skin: rash, exfoliative dermatitis, alopecia, pruritus, urticaria, angioedema, photosensitivity, Stevens-Johnson syndrome

Other: drug fever, chills, superinfection (limited to urinary tract), hypersensitivity reactions including anaphylaxis, lupus-like syndrome


Drug-drug. Anticholinergics: increased nitrofurantoin absorption and bioavailability

Drugs that can cause pulmonary toxicity: increased risk of pneumonitis

Hepatotoxic drugs: increased risk of hepatotoxicity

Magnesium salts: decreased nitrofurantoin absorption

Neurotoxic drugs: increased risk of neu-rotoxicity

Uricosurics (such as probenecid): decreased renal clearance and increased blood level of nitrofurantoin

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, blood urea nitrogen, creatinine: increased levels Granulocytes, platelets, hemoglobin: decreased levels

Urine glucose tests using Benedict's reagent or Fehling's solution: false-positive results

Drug-food. Any food: increased drug bioavailability

Patient monitoring

• Monitor patient's response to therapy. Assess urine culture and sensitivity tests.

Watch for and immediately report peripheral neuropathy.

Assess respiratory status. Watch for signs and symptoms of serious pulmonary hypersensitivity reaction.

Monitor CBC and liver function tests closely. Stay alert for evidence of hematologic and hepatic disorders.

• Evaluate patient for rash.

Patient teaching

• Instruct patient to take with food or milk at regular intervals around the clock.

• Advise patient to complete entire course of therapy.

• Tell patient not to take magnesium-containing drugs (such as antacids) during therapy.

• Caution patient not to drive or perform other hazardous activities until he knows how drug affects vision, concentration, and alertness.

Tell patient to immediately report fever, chills, cough, chest pain, difficulty breathing, rash, bleeding or easy bruising, dark urine, yellowing of skin or eyes, numbness or tingling of fingers or toes, or intolerable GI distress.

• Advise female patient to avoid taking drug during pregnancy, especially near term.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


A urinary antibacterial agent with a wide range of activity against both gram-positive and gram-negative organisms; also available as nitrofurantoin sodium for injection.
Farlex Partner Medical Dictionary © Farlex 2012


A derivative of nitrofuran, C8H6N4O5, used to treat bacterial infections of the urinary tract.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


A nitrofuran compound (O-[5-nitrofurfurylideneamino]hydantoin) with antimicrobial activity against a wide spectrum of gram-positive and gram-negative bacteria.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


A drug that damages bacterial DNA and is used to treat urinary tract infections. The drug is on the WHO official list. Brand names are Furadantin, Macrobid and Macrodantin.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005


Urinary antibacterial agent with a wide range of activity against both gram-positive and gram-negative organisms.
Medical Dictionary for the Dental Professions © Farlex 2012