Rantoin

• Approved Indications:
• Treatment of acute uncomplicated urinary tract infections (UTIs) caused by susceptible strains of Escherichia coli, Staphylococcus saprophyticus, Enterococcus faecalis, Klebsiella, and Enterobacter species.
• Prophylaxis of recurrent urinary tract infections in patients with frequent UTIs.
• Treatment of lower urinary tract infections (cystitis).
• Off-label Uses:
• Occasionally used in selected cases for complicated UTIs when other options are limited.
• Used for asymptomatic bacteriuria in pregnant women under specialist guidance.

• Adults:
• For uncomplicated UTIs: 50–100 mg orally every 6 hours for 5–7 days.
• For prophylaxis: 50–100 mg orally once daily or at bedtime.
• Elderly:
• Use cautiously due to increased risk of pulmonary and hepatic toxicity; dose adjustments not typically required but monitor closely.
• Pediatrics (≥1 month):
• 5–7 mg/kg/day divided into 4 doses, max 200 mg/day.
• Renal Impairment:
• Contraindicated if creatinine clearance <60 mL/min (risk of toxicity and reduced efficacy).
• Hepatic Impairment:
• No specific dosing adjustments; monitor liver function.
• Route: Oral administration.
• Duration: 5 to 7 days for treatment; longer for prophylaxis.

Nitrofurantoin is reduced by bacterial flavoproteins to reactive intermediates that damage bacterial DNA, ribosomal proteins, and other macromolecules, inhibiting vital biochemical processes. This causes bacterial cell death, predominantly effective against gram-positive and gram-negative bacteria in the urinary tract.

• Absorption: Rapid absorption from the gastrointestinal tract, about 90% bioavailability.
• Distribution: Concentrates mainly in urine; minimal plasma protein binding (~38%).
• Metabolism: Metabolized minimally by the liver.
• Half-life: Approximately 20 minutes to 1 hour.
• Excretion: Rapidly excreted unchanged in urine via glomerular filtration and tubular secretion.
• Onset: Therapeutic urinary levels achieved within hours.

• Pregnancy: FDA Category B — considered relatively safe during pregnancy, especially for lower UTIs; avoid near term due to risk of hemolytic anemia in newborns.
• Lactation: Excreted into breast milk in small amounts; caution advised; generally considered compatible with breastfeeding but monitor infant for adverse effects.

• Primary Class: Antibacterial agent
• Subclass: Nitrofuran derivative, urinary tract antiseptic

• Known hypersensitivity to nitrofurantoin or other nitrofuran derivatives.
• Renal impairment with creatinine clearance <60 mL/min.
• Pregnancy at term (38–42 weeks gestation).
• Neonates under 1 month old (risk of hemolytic anemia).
• History of cholestatic jaundice or hepatic dysfunction associated with nitrofurantoin.

• Risk of pulmonary toxicity (acute, subacute, or chronic), especially with prolonged use.
• Hepatotoxicity including cholestatic jaundice and hepatitis.
• Peripheral neuropathy risk, particularly in patients with diabetes, anemia, or renal impairment.
• Avoid in patients with significant renal dysfunction due to risk of drug accumulation and toxicity.
• Monitor for signs of allergic reactions or severe skin reactions.
• Discontinue if symptoms of pulmonary or hepatic toxicity develop.

• Common: Nausea, vomiting, loss of appetite, headache, discoloration of urine (brownish).
• Respiratory: Pulmonary fibrosis, pneumonitis (rare but serious).
• Neurological: Peripheral neuropathy, dizziness.
• Hepatic: Hepatitis, cholestatic jaundice (rare).
• Hypersensitivity: Rash, fever, eosinophilia.
• Others: Hemolytic anemia (especially in G6PD-deficient patients).

• Antacids containing magnesium trisilicate may reduce absorption.
• Probenecid and sulfinpyrazone may decrease renal excretion, increasing toxicity risk.
• Avoid concomitant use with other nephrotoxic drugs.
• No major CYP450 enzyme interactions reported.

• Recent guidelines recommend nitrofurantoin as a first-line agent for uncomplicated cystitis in women due to effectiveness and low resistance rates.
• Use is discouraged in patients with significant renal impairment.
• Increased emphasis on monitoring for pulmonary toxicity during prolonged therapy.
• Avoided in late pregnancy due to neonatal risk.

• Store at 20°C to 25°C (68°F to 77°F).
• Protect from moisture and light.
• Keep container tightly closed.
• Keep out of reach of children.
• No special refrigeration or reconstitution needed.