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Pronunciation |
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(nye
troe fyoor AN
toyn) |

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U.S. Brand
Names |
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Furadantin®; Macrobid®;
Macrodantin® |

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Generic
Available |
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Yes: Tablet and suspension |

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Canadian Brand
Names |
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Apo®-Nitrofurantoin; Nephronex®;
Novo-Furan |

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Pharmacological Index |
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Antibiotic, Miscellaneous |

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Use |
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Prevention and treatment of urinary tract infections caused by susceptible
gram-negative and some gram-positive organisms; Pseudomonas,
Serratia, and most species of Proteus are generally resistant to
nitrofurantoin |

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Pregnancy Risk
Factor |
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B |

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Contraindications |
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Hypersensitivity to nitrofurantoin or any component; renal impairment;
infants <1 month (due to the possibility of hemolytic
anemia) |

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Warnings/Precautions |
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Use with caution in patients with G-6-PD deficiency, patients with anemia,
vitamin B deficiency, diabetes mellitus or electrolyte abnormalities;
therapeutic concentrations of nitrofurantoin are not attained in urine of
patients with Clcr <40 mL/minute (elderly); use with caution if
prolonged therapy is anticipated due to possible pulmonary toxicity; acute,
subacute, or chronic (usually after 6 months of therapy) pulmonary reactions
have been observed in patients treated with nitrofurantoin; if these occur,
discontinue therapy; monitor closely for malaise, dyspnea, cough, fever,
radiologic evidence of diffuse interstitial pneumonitis or
fibrosis |

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Adverse
Reactions |
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Percentage unknown: Chest pains, chills, fever, fatigue, drowsiness,
headache, dizziness, rash, itching, lupus-like syndrome, exfoliative dermatitis,
stomach upset, diarrhea, loss of appetite/vomiting/nausea (most common), sore
throat, hemolytic anemia, hepatitis, hypersensitivity, increased LFTs, weakness,
paresthesia, numbness, arthralgia, cough, dyspnea, hypersensitivity, C.
difficile-colitis |

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Overdosage/Toxicology |
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Symptoms of overdose include vomiting
Supportive care only |

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Drug
Interactions |
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Decreased effect: Antacids, especially magnesium salts, decrease absorption
of nitrofurantoin; nitrofurantoin may antagonize effects of norfloxacin
Increased toxicity: Probenecid (decreases renal excretion of nitrofurantoin);
anticholinergic drugs increase absorption of nitrofurantoin
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Mechanism of
Action |
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Inhibits several bacterial enzyme systems including acetyl coenzyme A
interfering with metabolism and possibly cell wall
synthesis |

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Pharmacodynamics/Kinetics |
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Absorption: Well absorbed from GI tract; the macrocrystalline form is
absorbed more slowly due to slower dissolution, but causes less GI distress
Distribution: Vd: 0.8 L/kg; crosses the placenta; appears in
breast milk
Protein binding: ~40%
Metabolism: 60% of drug metabolized by body tissues throughout the body, with
exception of plasma, to inactive metabolites
Bioavailability: Increased by presence of food
Half-life: 20-60 minutes; prolonged with renal impairment
Elimination: As metabolites and unchanged drug (40%) in urine and small
amounts in bile; renal excretion via glomerular filtration and tubular secretion
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Usual Dosage |
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Oral:
Chronic therapy: 1-2 mg/kg/day in divided doses every 12-24 hours; maximum
dose: 100 mg/day
Adults: 50-100 mg/dose every 6 hours
Macrocrystal/monohydrate: 100 mg twice daily
Prophylaxis or chronic therapy: 50-100 mg/dose at bedtime
Dosing adjustment in renal impairment: Clcr <50
mL/minute: Avoid use
Avoid use in hemo and peritoneal dialysis and continuous arteriovenous or
venovenous hemofiltration (CAVH/CAVHD) |

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Dietary
Considerations |
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Alcohol: Avoid use |

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Monitoring
Parameters |
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Signs of pulmonary reaction, signs of numbness or tingling of the
extremities, periodic liver function tests |

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Test
Interactions |
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Causes false-positive urine glucose with
Clinitest® |

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Mental Health: Effects
on Mental Status |
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May cause drowsiness or dizziness |

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Mental Health:
Effects on Psychiatric
Treatment |
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Concurrent use with anticholinergic/antiparkinsonian medications may increase
the absorption of nitrofurantoin |

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Dental Health: Local
Anesthetic/Vasoconstrictor
Precautions |
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No information available to require special precautions |

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Dental Health:
Effects on Dental Treatment |
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No effects or complications reported |

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Patient
Information |
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Take per recommended schedule, at regular intervals around-the-clock.
Complete full course of therapy; do not skip doses. Maintain adequate hydration
(2-3 L/day of fluids unless instructed to restrict fluid intake). Diabetics
should consult prescriber if using Clinitest® for glucose
testing. Nitrofurantoin may discolor urine dark yellow or brown (normal). You
may experience nausea or vomiting or GI upset (small frequent meals, frequent
mouth care, sucking lozenges, or chewing gum may help); fatigue, drowsiness,
blurred vision (use caution when driving or engaging in tasks that require
alertness until response to drug is known). Report chest pains or palpitations;
pain on urination or blood in urine; skin rash; muscle weakness, pain, or
tremors; excessive fatigue or weakness; other persistent adverse effects; or if
condition does not improve. |

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Nursing
Implications |
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Higher peak serum levels may cause increased GI upset; administer
around-the-clock rather than 4 times/day, 3 times/day, etc, (ie, 12-6-12-6, not
9-1-5-9) to promote less variation in peak and trough serum levels; therapeutic
concentrations of nitrofurantoin are not attained in the urine of patients with
Clcr <40 mL/minute
Monitor for signs of pulmonary reaction, signs of numbness or tingling of the
extremities, periodic liver function tests |

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Dosage Forms |
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Capsule: 50 mg, 100 mg
Capsule:
Macrocrystal: 25 mg, 50 mg, 100 mg
Macrocrystal/monohydrate: 100 mg
Suspension, oral: 25 mg/5 mL (470 mL) |

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References |
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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.
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