Cefixime Dosing for Pediatric Pyelonephritis
For this 4-year-old child weighing 15.5 kg with pyelonephritis, administer cefixime 150 mg once daily (7.5 mL of 100 mg/5 mL suspension OR 4 mL of 200 mg/5 mL suspension) for 10 days as outpatient therapy. 1, 2
Dosing Calculation and Rationale
Weight-Based Dosing
- The child weighs 15.5 kg, which falls into the 12.6-20.5 kg weight range 1, 2
- The recommended dose for this weight range is 150 mg/day 1, 2
- This can be administered as a single daily dose, which is the standard FDA-approved regimen at 8 mg/kg/day 2
Formulation Options
You have two suspension concentration options:
- 100 mg/5 mL suspension: Give 7.5 mL once daily 1, 2
- 200 mg/5 mL suspension: Give 4 mL once daily 1, 2
Critical caveat: Always specify the concentration when prescribing in milliliters, as cefixime suspension comes in two different strengths and dosing errors are common 2
Duration of Therapy
- Treat for 10 days, which falls within the AAP-recommended 7-14 day range for pediatric UTIs/pyelonephritis 3
- This duration is appropriate for febrile UTIs, as shorter courses (1-3 days) have been shown to be inferior 3
- The 10-day duration is supported by evidence showing oral cefixime for 14 days is as effective as IV therapy followed by oral therapy for pyelonephritis 4
Clinical Considerations for Outpatient Management
When Outpatient Therapy is Appropriate
- The child must be able to tolerate oral medications (not vomiting excessively) 3, 5
- The child should not appear toxic on examination 3, 5
- If either of these conditions is not met, hospitalization with initial IV therapy is indicated 3, 5
Why Cefixime is Suitable
- Cefixime has broad-spectrum activity and is suitable as an empiric agent for most pediatric UTI cases 5
- It demonstrates 100% susceptibility against common urinary pathogens in pediatric studies 6
- Clinical trials show oral cefixime alone is as effective as IV therapy followed by oral therapy for acute pyelonephritis 4
- It achieves sufficient urinary concentrations with once-daily dosing 7
Administration Instructions
- Administer without regard to food 2
- Shake suspension well before each use 2
- After reconstitution, the suspension remains stable for 14 days at room temperature or refrigerated 2
- Discard any unused portion after 14 days 2
Important Pitfalls to Avoid
- Do not use tablets or capsules in place of suspension for this age group, as suspension achieves higher peak blood levels 2
- Ensure local antimicrobial susceptibility patterns support empiric cefixime use and adjust based on culture results when available 3
- Monitor for clinical improvement within 24-48 hours; if the child worsens or fails to improve, consider switching to parenteral therapy 3