Nitrofurantoin information from DrugsUpdate
L - Caution when used during lactation
FI - Food *
LI - Lab *
Nitrofurantoin is an antibiotic which is marketed under the following brand names; Furadantin, Macrobid, Macrodantin, Nitro Macro and Urantoin. It is usually used in treating urinary tract infection. Like many other drugs, it is often used against E Coli.
Nitrofurantoin interferes with cell metabolism and cell wall synthesis by inhibiting several enzyme systems including acetyl coenzyme A. It is bactericidal to most gram-positive and gram-negative urinary tract pathogens.
Readily absorbed from the GI tract. Food may increase bioavailability and prolong the duration of therapeutic urinary concentrations.
Concentrations in blood and body tissues are low; crosses the placenta and the blood-brain barrier and distributes in breast milk (trace amounts).
Hepatic and in most body tissues.
Via urine (30-40% of a dose excreted rapidly as unchanged drug); some tubular reabsorption may occur in acid urine. Plasma half-life: 0.3-1 hours.
Nausea, vomiting, anorexia, abdominal pain, diarrhoea; headache, drowsiness, vertigo, dizziness, nystagmus, benign intracranial hypertension; rash, urticaria, pruritus, fever, sialadenitis, angioedema, erythema multiforme, exfoliative dermatitis, pancreatitis, lupus-like syndrome, myalgia, arthralgia; acute pulmonary sensitivity reactions; megaloblastic anaemia, leucopenia, granulocytopenia or agranulocytosis, thrombocytopenia, aplastic anaemia, haemolytic anaemia (in G6PD-deficient patients); transient alopecia; brownish discolouration of urine.
Potentially Fatal: Peripheral polyneuropathy, hepatotoxicity, anaphylaxis, Stevens-Johnson syndrome, interstitial pneumonitis, pulmonary fibrosis.
Monitor patient for signs and symptoms of pulmonary hypersensitivity reaction. Monitor patient for signs and symptoms of liver dysfunction.
Symptoms include vomiting. Management is supportive; dialysable
Elderly. Monitor hepatic and pulmonary function during prolonged therapy. Pre-existing pulmonary, hepatic, neurological, or allergic disorders, predisposition to peripheral neuropathy e.g. renal impairment, anaemia, DM, electrolyte imbalance, debility, vitamin B deficiency. Withdraw if signs of peripheral neuropathy occur. Lactation.
Reduced excretion with probenecid or sulfinpyrazone. Absorption reduced by magnesium trisilicate. Antagonistic effects with quinolone antibacterials. Reduced effects with carbonic anhydrase inhibitors or urinary alkalinisers.
Food may increase bioavailability and prolong therapeutic concentrations in urine.
Acute uncomplicated urinary tract infections
Adult: 50-100 mg 4 times daily for 7 days. Dual-release preparation: 100 mg bid.
Child: >3 months and older children: 3 mg/kg daily in 4 divided doses.
Prophylaxis of uncomplicated urinary tract infections
Adult: 50-100 mg at bedtime.
Child: >3 months and older children: 1 mg/kg once daily.
Should be taken with food. (Take w/ or immediately after meals.)
List of Contraindications
Contraindicated in pregnancy
Category B: Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).
Caution when used during lactation
Contraindicated in infants younger than 1 month of age. Monohydrate microcrystals: Safety and efficacy not established in children younger than 12 years of age.
Severe renal impairment (anuria, oliguria, significantly elevated serum creatinine, CrCl <60 ml/min). Hypersensitivity to nitrofurans, G6PD deficiency, infants <3 months. Pregnancy at term, during labour and delivery, or when the onset of labour is imminent.
Store at 15-30°C (59-86°F).
False-positive test for urinary glucose using cupric sulfate solution.