What is the recommended dosage of cefuroxime axetil (Cefuroxime Axetil) for an 8-month-old infant with a urinary tract infection (UTI) and normal renal function?

Cefuroxime Axetil Dosing for UTI in an 8-Month-Old Infant

For an 8-month-old infant with a UTI, administer cefuroxime axetil at 20-30 mg/kg/day divided into two doses (every 12 hours) for 7-14 days, with 10 days being the most commonly recommended duration. 1, 2

Specific Dosing Recommendations

Standard Dosing for Infants

• The FDA label for cefuroxime indicates that pediatric patients above 3 months of age should receive 50-100 mg/kg/day in equally divided doses every 6-8 hours for most infections 3
• For UTIs specifically, the lower end of this range (20-30 mg/kg/day divided twice daily) has been shown effective in clinical trials 4, 5
• A practical dosing approach: For an 8-month-old weighing approximately 8-9 kg, give 125 mg twice daily (approximately 28-31 mg/kg/day) 4, 5

Treatment Duration

• The American Academy of Pediatrics recommends 7-14 days total duration for febrile UTI, with 10 days being the most common duration 1, 2
• Studies have shown that 2-day therapy may be as effective as 10-day therapy for uncomplicated UTIs in children, though the evidence is limited and 7-10 days remains standard practice 5
• Do not treat for less than 7 days for febrile UTI, as shorter courses are inferior 1, 2

Clinical Context and Route Selection

Oral vs. Parenteral Therapy

• Oral cefuroxime axetil is appropriate if the infant is well-appearing, stable, and able to retain oral medications 1, 2
• Parenteral therapy (ceftriaxone 50 mg/kg IV/IM once daily) should be reserved for infants who appear toxic, cannot retain oral intake, or have uncertain compliance 1, 2
• Oral and parenteral routes are equally efficacious when the infant can tolerate oral medications 2

Administration Considerations

• Cefuroxime axetil is available as an oral suspension containing 125 mg or 250 mg per dose, specifically formulated for pediatric use 4
• Administer with food or milk to enhance absorption—bioavailability is 68% when taken after a meal 4
• The suspension should be given twice daily (every 12 hours) for optimal efficacy 4, 5

Critical Management Steps

Before Starting Treatment

• Obtain urine culture via catheterization or suprapubic aspiration BEFORE starting antibiotics 2
• Diagnosis requires both pyuria (≥5 WBC/HPF or positive leukocyte esterase) AND ≥50,000 CFU/mL of a single uropathogen on culture 2

Monitoring Response

• Clinical improvement (defervescence) should occur within 24-48 hours of starting appropriate therapy 1, 2
• If fever persists beyond 48 hours despite appropriate antibiotics, this constitutes an "atypical" UTI requiring further evaluation 1
• Follow-up in 1-2 days is critical to confirm the infant is responding to antibiotics and fever has resolved 2

Antibiotic Adjustment

• Adjust therapy based on culture and sensitivity results when available 1, 2
• Consider local antibiotic resistance patterns—cefuroxime axetil should only be used if local E. coli resistance rates are acceptable 6
• All 37 uropathogens tested in one pediatric study were sensitive to cefuroxime axetil in vitro 5

Imaging Recommendations for This Age Group

• Obtain renal and bladder ultrasound (RBUS) for all febrile infants <2 years with first UTI to detect anatomic abnormalities 1, 2
• The ultrasound should be performed within 6 weeks of the UTI if typical infection, or during acute infection if atypical 7
• Voiding cystourethrography (VCUG) is NOT routinely recommended after first UTI 1, 2
• VCUG is only indicated if RBUS shows hydronephrosis, scarring, or findings suggesting high-grade vesicoureteral reflux or obstruction, OR after a second febrile UTI 2

Common Pitfalls to Avoid

• Do not use nitrofurantoin for febrile UTIs in infants, as it does not achieve adequate serum/parenchymal concentrations to treat pyelonephritis 1, 2
• Do not fail to obtain urine culture before starting antibiotics—this is the only opportunity for definitive diagnosis 2
• Do not delay treatment if febrile UTI is suspected—early treatment (within 48 hours of fever onset) reduces renal scarring risk by more than 50% 1, 2
• Do not use bag collection for culture due to unacceptably high false-positive rates (85% false-positive rate) 2

Safety and Adverse Effects

• Adverse reactions to cefuroxime axetil are generally mild and transient, including gastrointestinal disturbances (diarrhea, nausea, vomiting) 4
• In clinical trials, drug-related adverse events occurred in 10% of patients, including diarrhea in 4% 8
• Candida vaginitis occurred in 8% of patients in one study, though this was in adult women 9

Long-Term Considerations

• Approximately 15% of children develop renal scarring after first UTI, which can lead to hypertension (5%) and chronic kidney disease 2, 6
• Instruct parents to seek prompt medical evaluation (ideally within 48 hours) for any future febrile illnesses to detect recurrent UTIs early 2
• No routine scheduled follow-up visits are necessary after successful treatment of a first uncomplicated UTI, but maintain a low threshold for evaluation of future fevers 2