What formulations of nitrofurantoin (antibiotic) are available in Canada for a 6-year-old female (YOF) patient with a urinary tract infection (UTI) requiring 35mg four times a day (QID)?

Nitrofurantoin Formulations Available in Canada for a 6-Year-Old Female with UTI Requiring 35mg QID

For a 6-year-old female with UTI requiring 35mg QID dosing of nitrofurantoin in Canada, the macrocrystalline formulation is the most appropriate option, as it can be dosed at 50-100mg QID with a maximum of 100mg per dose. 1

Available Formulations and Dosing

• Nitrofurantoin is recommended at 5-7 mg/kg/day divided into 4 doses (QID) for pediatric UTIs, with a maximum dose of 100mg per dose 1
• For a 6-year-old female requiring 35mg QID (which falls within the recommended dosing range), the following formulations are available:
  • Nitrofurantoin macrocrystals: 50-100mg QID for 5 days 1
  • Nitrofurantoin monohydrate/macrocrystals: 100mg BID for 5 days 1
  • Nitrofurantoin macrocrystals prolonged release: 100mg BID for 5 days 1

Clinical Considerations for Pediatric Patients

• Nitrofurantoin should not be used in infants younger than 4 months due to risk of hemolytic anemia 1
• For children with uncomplicated UTI, nitrofurantoin is appropriate for lower urinary tract infections but should not be used for pyelonephritis or upper tract infections 1
• The oral formulation should not be used for pyelonephritis or perinephric abscess as it does not achieve adequate tissue concentrations 1
• Recommended duration of treatment is 7 days or at least 3 days after obtaining a sterile urine 1

Important Cautions and Monitoring

• Nitrofurantoin has a short elimination half-life in blood/plasma, which necessitates the QID dosing for standard formulations 2
• The drug is rapidly absorbed and quickly distributed into body fluids, with excretion primarily through urine and bile 2
• For the 6-year-old patient requiring 35mg QID, the macrocrystalline formulation would be most appropriate as it can be dosed four times daily and the 50mg capsules could be compounded to achieve the 35mg dose 1
• Bioavailability of nitrofurantoin is affected by formulation differences, drug particle size, and dosage form 2
• Regular monitoring for adverse effects is recommended, particularly with longer-term use 3

Alternative Considerations

• If nitrofurantoin is unavailable or contraindicated, alternative oral treatments for pediatric UTI include:
  • Amoxicillin-clavulanate: 20-40 mg/kg/day in 3 doses 1
  • Cephalosporins (e.g., cephalexin): 50-100 mg/kg/day in 4 doses 1
  • Trimethoprim-sulfamethoxazole: 6-12 mg/kg trimethoprim and 30-60 mg/kg sulfamethoxazole per day in 2 doses 1

Efficacy Considerations

• Nitrofurantoin remains effective against many drug-resistant uropathogens and is considered a first-line therapy for uncomplicated lower UTIs 3, 4
• In randomized controlled trials, nitrofurantoin has shown significant efficacy in achieving both bacteriological cure and symptomatic relief compared to placebo 4