Nitrofurantoin
Nitrofurantoin (Furadantin)
Nitrofurantoin
( nye-troh-fyour- AN-toyn)
Pregnancy Category: B Apo-Nitrofurantoin Furadantin (Rx)
Nitrofurantoin macrocrystals
Nitrofurantoin macrocrystals (Macrobid, Macrodantin)
Nitrofurantoin
( nye-troh-fyour- AN-toyn)
Pregnancy Category: B Macrobid Macrodantin Nephronex Novo-Furan (Rx)

Classification: Urinary germicide

See Also: See also Anti-Infectives .

Action/Kinetics: Interferes with bacterial carbohydrate metabolism by inhibiting acetyl coenzyme A; also interferes with bacterial cell wall synthesis. Bacteriostatic at low concentrations and bactericidal at high concentrations. Tablets are readily absorbed from the GI tract; bioavailability is increased by food. t 1/2: 20 min (60 min in anephric clients). Urine levels: 50-250 mcg/mL. If the C _CR is less than 40 mL/min, urine antibacterial levels are inadequate, with the subsequent higher blood levels increasing the possibility of toxicity. Antibacterial activity is best in an acid urine. From 30% to 50% excreted unchanged in the urine. Nitrofurantoin macrocrystals (Macrodantin) are available; this preparation maintains effectiveness while decreasing GI distress.

Uses: UTIs due to susceptible strains of Escherichia coli, Staphylococcus aureus (not for treatment of pyelonephritis or perinephric abscesses), enterococci, and certain strains of Enterobacter and Klebsiella.

Contraindications: Anuria, oliguria, and clients with impaired renal function (C _CR below 40 mL/min); pregnant women, especially near term; infants less than 1 month of age; and lactation.

Special Concerns: Use with extreme caution in anemia, diabetes, electrolyte imbalance, avitaminosis B, or a debilitating disease. Safety during lactation has not been established.

Side Effects: Nitrofurantoin is a potentially toxic drug with many side effects. GI: N&V, anorexia, diarrhea, abdominal pain, parotitis, pancreatitis. CNS: Headache, dizziness, vertigo, drowsiness, nystagmus, confusion, depression, euphoria, psychotic reactions (rare). Hematologic: Leukopenia, thrombocytopenia, eosinophilia, megaloblastic anemia, agranulocytosis granulocytopenia, hemolytic anemia (especially in clients with G6PD deficiency). Allergic: Drug fever, skin rashes, pruritus, urticaria, angioedema, exfoliative dermatitis, erythema multiforme (rarely, Stevens-Johnson syndrome), anaphylaxis arthralgia, myalgia, chills, sialadenitis, asthma symptoms in susceptible clients; maculopapular, erythematous, or eczematous eruption. Pulmonary: Sudden onset of dyspnea, cough, chest pain, fever and chills; pulmonary infiltration with consolidation or pleural effusion on x-ray, elevated ESR, eosinophilia. After subacute or chronic use: dyspnea, nonproductive cough, malaise, interstitial pneumonitis. Permanent impairment of pulmonary function with chronic therapy. A lupus-like syndrome associated with pulmonary reactions. Hepatic: Hepatitis, cholestatic jaundice, chronic active hepatitis, hepatic necrosis (rare). CV: Benign intracranial hypertension, changes in ECG, collapse, cyanosis. Miscellaneous: Peripheral neuropathy, asthenia, alopecia, superinfections of the GU tract, muscle pain.

Laboratory Test Alterations: AST, ALT, serum phosphorus. Hemoglobin.

Overdose Management: Symptoms: Vomiting (most common). Treatment: Induce emesis. High fluid intake to promote urinary excretion. The drug is dialyzable.

Drug Interactions: Acetazolamide / Nitrofurantoin effect R/T urine alkalinity produced by acetazolamide Antacids, oral / Nitrofurantoin effect R/T GI tract absorption Anticholinergic drugs / Nitrofurantoin effect R/T stomach absorption Magnesium trisilicate / Nitrofurantoin absorption from GI tract Nalidixic acid / Effect of nalidixic acid Probenecid / High doses secretion of nitrofurantoin toxicity Sodium bicarbonate / Nitrofurantoin effect R/T urine alkalinity produced by sodium bicarbonate

How Supplied: Capsule: 25 mg, 50 mg, 100 mg; Suspension: 25 mg/5 mL (Nitrofurantoin)

Dosage
?Capsules, Oral Suspension UTIs.
Adults: 50-100 mg q.i.d., not to exceed 600 mg/day. For cystitis, Macrobid is given in doses of 100 mg b.i.d. for 7 days. Pediatric, 1 month of age and over: 5-7 mg/kg/day in four equal doses.
Prophylaxis of UTIs.
Adults: 50-100 mg at bedtime. Pediatric, 1 month of age and over: 1 mg/kg/day at bedtime or in two divided doses daily.