nitrofurantoin
(nye troe fyoor an' toyn)
nitrofurantoin
Apo-Nitrofurantoin (CAN), Furadantin, Novo-Furantoin (CAN)
nitrofurantoin macrocrystals
Macrobid, Macrodantin
Pregnancy Category B
Drug classes
Urinary tract anti-infective
Antibacterial
Therapeutic actions
Bacteriostatic in low concentrations, possibly by interfering with bacterial carbohydrate metabolism; bactericidal in high concentrations, possibly by disrupting bacterial cell wall formation, causing cell death.
Indications
· Treatment of UTIs caused by susceptible strains of Escherichia coli, Staphylococcus aureus, Klebsiella, Enterobacter, Proteus
· Prophylaxis or long-term suppression of UTIs
Contraindications and cautions
· Contraindicated with allergy to nitrofurantoin, renal dysfunction; pregnancy, lactation.
· Use cautiously in patients with G6PD deficiency, anemia, diabetes.
Available forms
Capsules—25, 50, 100 mg; Dual-release capsules—100 mg; oral suspension—25 mg/5 mL
Dosages
ADULTS
50–100 mg PO qid for 10–14 days or 100 mg bid for 7 days (Macrobid). Do not exceed 400 mg/day.
· Long-term suppressive therapy: 50–100 mg PO hs.
PEDIATRIC PATIENTS
5–7 mg/kg/day in four divided doses PO. Not recommended in children < 1 mo.
· Long-term suppressive therapy: As low as 1 mg/kg/day PO in one to two doses.
Pharmacokinetics
Route | Onset | Peak |
Oral | Rapid | 30 min |
Metabolism: Hepatic; T1/2: 20–60 min
Distribution: Crosses placenta; enters breast milk
Excretion: Urine
Adverse effects
· CNS: Peripheral neuropathy, headache, dizziness, nystagmus, drowsiness, vertigo
· Dermatologic: Exfoliative dermatitis, Stevens-Johnson syndrome, alopecia, pruritus, urticartia, angioedema
· GI: Nausea, abdominal cramps, vomiting, diarrhea, anorexia, parotitis, pancreatitis, hepatotoxicity
· Hematologic: Hemolytic anemia in G6PD deficiency; granulocytopenia, agranulocytosis, leukopenia, thrombocytopenia, eosinophilia, megaloblastic anemia
· Respiratory: Pulmonary hypersensitivity
· Other: Superinfections of the GU tract; hypotension; muscular aches; brown-rust urine
Interactions
Drug-drug
· Delayed or decreased absorption with magnesium trisilicate, magaldrate
Drug-lab test
· False elevations of urine glucose, bilirubin, alkaline phosphatase, BUN, urinary creatinine
· False-positive urine glucose when using Benedict's or Fehling's reagent
Nursing considerations
Assessment
· History: Allergy to nitrofurantoin, renal dysfunction, G6PD deficiency, anemia, diabetes, pregnancy, lactation
· Physical: Skin color, lesions; orientation, reflexes; R, adventitious sounds; liver evaluation; CBC; LFTs, renal function tests; serum electrolytes; blood, urine glucose, urinalysis
Interventions
· Arrange for culture and sensitivity tests before and during therapy.
· Give with food or milk to prevent GI upset.
· Continue drug for at least 3 days after a sterile urine specimen is obtained.
· Monitor clinical response; if no improvement is seen or a relapse occurs, send urine for repeat culture and sensitivity.
· WARNING: Monitor pulmonary function carefully; reactions can occur within hours or weeks of nitrofurantoin therapy.
· Arrange for periodic CBC and LFTs during long-term therapy.
Teaching points
· Take drug with food or milk. Complete the full course of drug therapy to ensure a resolution of the infection. Take this drug at regular intervals around the clock; consult your nurse or pharmacist to set up a convenient schedule.
· You may experience these side effects: Nausea, vomiting, abdominal pain (eat frequent small meals); diarrhea; drowsiness, blurring of vision, dizziness (observe caution driving or using dangerous equipment); brown or yellow-rust urine (expected effect).
· Report fever, chills, cough, chest pain, difficulty breathing, rash, numbness or tingling of the fingers or toes.
Adverse effects in Italic are most common; those in Bold are life-threatening.
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