Adult: In acute cases: As immediate-release preparation: 50 mg 4 times daily for 7 days. As dual-release preparation: 100 mg 12 hourly for 7 days. In severe chronic recurrent cases: As immediate-release preparation: 100 mg 4 times daily for 7 days. Child: In acute cases: As immediate-release preparation: >3 months to <12 years 3 mg/kg daily in 4 divided doses for 7 days. As dual-release preparation: >12 years Same as adult dose. Dosage recommendations may vary among countries or individual products. Refer to specific product guidelines.
Oral Prophylaxis of uncomplicated urinary tract infections
Adult: For long-term suppressive therapy: As immediate-release preparation: 50-100 mg once daily. For surgical prophylaxis: As immediate-release preparation: 50 mg 4 times daily, given for the duration of the procedure and 3 days thereafter. As dual-release preparation: 100 mg 12 hourly, given on the day of the procedure and 3 days thereafter. Child: For long-term suppressive therapy: As immediate-release preparation: >3 months 1 mg/kg once daily. For surgical prophylaxis: As dual-release preparation: >12 years Same as adult dose. Dosage recommendations may vary among countries or individual products. Refer to specific product guidelines.
Renal Impairment
CrCl (mL/min)
Dosage
<60
Contraindicated.
Administration
Should be taken with food. Take w/ or immediately after meals.
Contraindications
Hypersensitivity. G6PD deficiency, acute porphyria. Renal impairment (including anuria, oliguria, eGFR <45 mL/min or CrCl <60 mL/min, or clinically significant elevated serum creatinine); history of cholestatic jaundice or hepatic dysfunction associated with previous nitrofurantoin use. Infants <3 months old. Pregnancy (38-42 weeks gestation, during labour and delivery, or when the onset of labour is imminent).
Special Precautions
Patient with pulmonary disease, neurological disorders, allergic diathesis, anaemia, diabetes mellitus, electrolyte imbalance, debilitating conditions, vitamin B (particularly folate) deficiency. Hepatic impairment. Children. Pregnancy (early stage) and lactation.
Adverse Reactions
Significant: Haemolytic anaemia, superinfection, Clostridium difficile-associated diarrhoea, optic neuritis. Blood and lymphatic system disorders: Granulocytopenia, eosinophilia, megaloblastic anaemia. Rarely, aplastic anaemia. Eye disorders: Amblyopia, nystagmus. Gastrointestinal disorders: Nausea, flatulence, dyspepsia, diarrhoea, abdominal pain, constipation, emesis, sialadenitis, pancreatitis. General disorders and administration site conditions: Fever, chills, malaise, asthenia. Immune system disorders: Anaphylaxis. Metabolism and nutrition disorders: Anorexia. Musculoskeletal and connective tissue disorders: Arthralgia. Nervous system disorders: Headache, dizziness, drowsiness. Rarely, increased intracranial pressure. Psychiatric disorders: Rarely, confusion, depression, psychotic reactions. Skin and subcutaneous tissue disorders: Pruritus, urticaria, alopecia, angioedema, drug rash with eosinophilia and systemic symptoms (DRESS), lupus-like syndrome associated with pulmonary reaction, exfoliative dermatitis and erythema multiforme (including Stevens-Johnson syndrome); maculopapular, erythematous, or eczematous eruption. Potentially Fatal: Acute, subacute, or chronic pulmonary reactions, peripheral neuropathy. Rarely, hepatic reactions (e.g. hepatitis, autoimmune hepatitis, cholestatic jaundice, chronic active hepatitis, and hepatic necrosis).
This drug may cause dizziness or drowsiness, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor CBC; LFT and renal function periodically. Monitor signs or symptoms of hepatitis (particularly in long-term use), pulmonary reaction (e.g. malaise, dyspnoea, cough, fever); numbness or tingling of the extremities.
Overdosage
Symptoms: Gastric irritation, nausea, and vomiting. Management: Induce emesis or perform gastric lavage. Haemodialysis may be performed. Maintain high fluid intake to promote urinary excretion.
Drug Interactions
Increased absorption with agents that delay gastric emptying. Decreased absorption with antacids containing Mg trisilicate. Decreased renal excretion with uricosuric drugs (e.g. probenecid, sulfinpyrazone). Decreased antibacterial activity with carbonic anhydrase inhibitors. Antagonistic effects with quinolone antibacterials. May diminish the therapeutic effect of typhoid vaccine.
Food Interaction
Increased absorption with food.
Lab Interference
May cause a false-positive reaction for urinary glucose using Benedict's and Fehling's solutions.
Action
Description: Mechanism of Action: Nitrofurantoin is a broad-spectrum nitrofuran antibacterial agent which is active against the majority of urinary pathogens. It is reduced by a wide range of enzymes including bacterial flavoproteins to reactive intermediates which inactivate or alter bacterial ribosomal proteins and other macromolecules resulting in inhibition of the vital biochemical processes of protein synthesis, aerobic energy metabolism, DNA, RNA, and cell wall synthesis. Pharmacokinetics: Absorption: Readily absorbed from the gastrointestinal tract; macrocrystalline form is absorbed more slowly. Increased bioavailability with food by approx 40%. Distribution: Crosses the placenta and blood-brain barrier and enters breast milk. Volume of distribution: 0.8 L/kg. Plasma protein binding: 60-90%. Metabolism: Metabolised in the liver and most body tissues to inactive metabolites. Excretion: As susp: Via urine (approx 40-45%) and faeces (small amount) as metabolites and unchanged drug. As macrocrystals: Via urine (20-25%, as unchanged drug). Elimination half-life: 20-60 minutes.
Chemical Structure
Nitrofurantoin Source: National Center for Biotechnology Information. PubChem Database. Nitrofurantoin, CID=6604200, https://pubchem.ncbi.nlm.nih.gov/compound/Nitrofurantoin (accessed on Jan. 22, 2020)
Storage
Tab: Store below 25°C. Cap: Store between 15-30°C. Suspension: Store between 20-25°C. Protect from light.
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