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Medication Safety Issues
International issues:
Macrobid® may be confused with Mikrozid® which is a brand name for ethanol/propanol combination in Great Britain
Pronunciation
(nye troe fyoor AN toyn)
U.S. Brand Names
Generic Available
Yes: Excludes suspension
Canadian Brand Names
Pharmacologic Category
Use
Prevention and treatment of urinary tract infections caused by susceptible strains of E. coli, S. aureus, Enterococcus, Klebsiella, and Enterobacter
Pregnancy Risk Factor
B (contraindicated at term)
Pregnancy Implications
Teratogenic effects have not been observed in animal studies, however, may cause hemolytic anemia in infants. Use of nitrofurantoin is contraindicated at term (38-42 weeks gestation), during labor and delivery, or when the onset of labor is imminent.
Lactation
Enters breast milk/not recommended (infants <1 month); AAP rates “compatible”
Breast-Feeding Considerations
Excreted in trace amounts in breast milk; may cause hyperbilirubinemia or hemolytic anemia in infants (<1 month of age). AAP rates “compatible.” Use caution in G6PD deficiency.
Contraindications
Hypersensitivity to nitrofurantoin or any component of the formulation; renal impairment (anuria, oliguria, significantly elevated serum creatinine, or Clcr< 60 mL/minute); infants <1 month (due to the possibility of hemolytic anemia); pregnancy at term (38-42 weeks gestation), during labor and delivery, or when the onset of labor is imminent
Warnings/Precautions
Concerns related to adverse effects:
• Hepatic reactions: Rare, but severe hepatic reactions have been associated with use (onset may be insidious); discontinue immediately if hepatitis occurs.
• Peripheral neuropathy: Has been associated with peripheral neuropathy (rare); risk may be increased by renal impairment, diabetes, vitamin B deficiency, or electrolyte imbalance; use caution.
• Pulmonary toxicity: Acute, subacute, or chronic (usually after 6 months of therapy) pulmonary reactions have been observed; if these occur, discontinue therapy immediately. Monitor closely for malaise, dyspnea, cough, fever, radiologic evidence of diffuse interstitial pneumonitis or fibrosis.
• Superinfection: Prolonged use may result in fungal or bacterial superinfection, including C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.
Disease-related concerns:
• Anemia: Use with caution in patients with anemia.
• Renal impairment: Therapeutic concentrations are not attained in urine of patients with Clcr<60 mL/minute.
Special populations:
• G6PD deficiency: Use with caution in patients with G6PD deficiency .
• Pediatrics: Safety and efficacy have not been established in children <1 month of age.
Adverse Reactions
Frequency not defined.
Cardiovascular: Chest pain, cyanosis, ECG changes
Central nervous system: Bulging fontanels (infants), chills, confusion, depression, dizziness, drowsiness, fever, headache, malaise, pseudotumor cerebri, psychotic reaction, vertigo
Dermatologic: Alopecia, angioedema, erythema multiforme, exfoliative dermatitis, pruritus, rash (eczematous, erythematous, maculopapular), Stevens-Johnson syndrome, urticaria
Gastrointestinal: Abdominal pain, C. difficile colitis, constipation, diarrhea, dyspepsia, flatulence, nausea, pancreatitis, sialadenitis, vomiting
Hematologic: Agranulocytosis, eosinophilia, granulocytopenia, hemolytic anemia, leukopenia, megaloblastic anemia, thrombocytopenia
Hepatic: Cholestasis, hepatitis, hepatic necrosis, transaminases increased, jaundice (cholestatic)
Neuromuscular & skeletal: Arthralgia, myalgia, numbness, paresthesia, peripheral neuropathy, weakness
Ocular: Amblyopia, nystagmus, optic neuritis
Respiratory: Cough, dyspnea, pneumonitis, pulmonary fibrosis (with long-term use), pulmonary infiltration
Miscellaneous: Anaphylaxis, hypersensitivity (including acute pulmonary hypersensitivity), lupus-like syndrome
Drug Interactions
Antacids: Magnesium trisilicate-containing antacids may decrease the absorption of nitrofurantoin.
Uricosuric agents (probenecid, sulfinpyrazone): May decrease renal excretion of nitrofurantoin.
Ethanol/Nutrition/Herb Interactions
Ethanol: Avoid ethanol (may increase CNS depression).
Food: Nitrofurantoin serum concentrations may be increased if taken with food.
Storage
Store at room temperature 15°C to 30°C (59°F to 86°F).
Mechanism of Action
Inhibits several bacterial enzyme systems including acetyl coenzyme A interfering with metabolism and possibly cell wall synthesis
Pharmacodynamics/Kinetics
Absorption: Well absorbed; macrocrystalline form absorbed more slowly due to slower dissolution (causes less GI distress)
Distribution: Vd: 0.8 L/kg; crosses placenta; enters breast milk
Protein binding: 60% to 90%
Metabolism: Body tissues (except plasma) metabolize 60% of drug to inactive metabolites
Bioavailability: Increased with food
Half-life elimination: 20-60 minutes; prolonged with renal impairment
Excretion:
Suspension: Urine (40%) and feces (small amounts) as metabolites and unchanged drug
Macrocrystals: Urine (20% to 25% as unchanged drug)
Dosage
Oral:
Children >1 month:
UTI treatment (Furadantin®, Macrodantin®): 5-7 mg/kg/day in divided doses every 6 hours; maximum: 400 mg/day. Administer for 7 days or at least 3 days after obtaining sterile urine
UTI prophylaxis (Furadantin®, Macrodantin®): 1-2 mg/kg/day in divided doses every 12-24 hours; maximum: 100 mg/day
Children >12 years: UTI treatment (Macrobid®): 100 mg twice daily for 7 days
Adults:
UTI treatment:
Furadantin®, Macrodantin®: 50-100 mg/dose every 6 hours; administer for 7 days or at least 3 days after obtaining sterile urine
Macrobid®: 100 mg twice daily for 7 days
UTI prophylaxis (Furadantin®, Macrodantin®): 50-100 mg/dose at bedtime
Dosing adjustment in renal impairment: Clcr <60 mL/minute: Contraindicated
Contraindicated in hemo- and peritoneal dialysis and continuous arteriovenous or venovenous hemofiltration
Administration: Oral
Administer with meals to improve absorption and decrease adverse effects; suspension may be mixed with water, milk, fruit juice, or infant formula. Shake suspension well before use.
Monitoring Parameters
Signs of pulmonary reaction, signs of numbness or tingling of the extremities, periodic liver function tests
Test Interactions
False-positive urine glucose (Benedict's and Fehling's methods); no false positives with enzymatic tests
Patient Education
Do not take any new medication during therapy unless approved by prescriber. Take entire prescription, even if you are feeling better. Take with food. Suspension may be mixed with water, milk, fruit juice, or infant formula. Shake suspension well before use. Maintain adequate hydration (2-3 L/day of fluids) unless instructed to restrict fluid intake. If you have diabetes, drug may cause false test results with Clinitest® urine glucose monitoring; use of another type of glucose monitoring is preferable. May cause nausea or vomiting (small, frequent meals, frequent mouth care, sucking lozenges, or chewing gum may help); or diarrhea (buttermilk, boiled milk, or yogurt may help). Report immediately and rash; swelling of face, tongue, mouth, or throat; or chest tightness. Report if condition being treated worsens or does not improve by the time prescription is completed.
Geriatric Considerations
Because of nitrofurantoin's decreased efficacy in patients with a Clcr <60 mL/minute and its side effect profile, it is not an antibiotic of choice for acute or prophylactic treatment of urinary tract infections in the elderly. An increased rate of severe hepatic toxicity has been suggested by postmarketing reports.
Dental Health: Effects on Dental Treatment
No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Mental Health: Effects on Mental Status
May cause drowsiness or dizziness
Mental Health: Effects on Psychiatric Treatment
Concurrent use with anticholinergic/antiparkinsonian medications may increase the absorption of nitrofurantoin
Nursing: Physical Assessment/Monitoring
Assess allergy history and renal status prior to beginning therapy. Assess results of laboratory tests, therapeutic effectiveness, and adverse response. Advise patients with diabetes about use of Clinitest® (may cause false-positive urine glucose). Teach patient proper use, possible side effects/appropriate interventions, and adverse symptoms to report.
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule [macrocrystal]: 50 mg, 100 mg
Macrodantin®: 25 mg, 50 mg, 100 mg
Capsule [macrocrystal/monohydrate]: 100 mg [nitrofurantoin macrocrystal 25% and nitrofurantoin monohydrate 75%]
Macrobid®: 100 mg [nitrofurantoin macrocrystal 25% and nitrofurantoin monohydrate 75%]
Suspension, oral:
Furadantin®: 25 mg/5 mL (470 mL)
Pricing: U.S. (www.drugstore.com)
Capsules (Macrobid)
100 mg (20): $49.99
Capsules (Macrodantin)
25 mg (30): $36.99
50 mg (30): $41.99
100 mg (30): $68.99
Capsules (Nitrofurantoin Macrocrystal)
50 mg (30): $27.99
100 mg (30): $56.27
Capsules (Nitrofurantoin Monohyd Macro)
100 mg (20): $26.99
Suspension (Furadantin)
25 mg/5 mL (60): $77.04
References
“American Academy of Pediatrics Committee on Drugs. The Transfer of Drugs and Other Chemicals Into Human Milk,” Pediatrics, 2001, 108(3):776-89.
Brendstrup L, Hjelt K, Petersen KE, et al, “Nitrofurantoin Versus Trimethoprim Prophylaxis in Recurrent Urinary Tract Infections in Children,” Acta Paediatr Scand, 1990. 79(12):1225-34.
Burgert SJ, Burke JP, and Box TD, “Reversible Nitrofurantoin-Induced Chronic Active Hepatitis and Hepatic Cirrhosis in a Patient Awaiting Liver Transplantation,” Transplantation, 1995, 59(3):448-9.
Coraggio MJ, Gross TP, and Roscelli JD, “Nitrofurantoin Toxicity in Children,” Pediatr Infect Dis J, 1989, 8(3):163-6.
D'Arcy PF, “Nitrofurantoin,” Drug Intell Clin Pharm, 1985, 19(7-8):540-7.
Penn RG and Griffin HP, “Adverse Reactions to Nitrofurantoin in the United Kingdom, Sweden, and Holland,” Br Med J (Clin Res Ed), 1982, 284(6327):1440-2.
“Practice Parameter: The Diagnosis, Treatment, and Evaluation of the Initial Urinary Tract Infection in Febrile Infants and Young Children. American Academy of Pediatrics. Committee on Quality Improvement. Subcommittee on Urinary Tract Infection,” Pediatrics, 1999, 103(4 Pt 1):843-52.
International Brand Names
Lexi-Comp.com
Last full review/revision May 2008
Content last modified May 2008
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