Amikacin Dosing for a 3-Year-Old Child
For a 3-year-old child with normal renal function, administer amikacin 15-22.5 mg/kg/day divided every 8 hours (5-7.5 mg/kg every 8 hours), with once-daily dosing of 15-20 mg/kg/day as an acceptable alternative. 1, 2
Standard Dosing Regimen
The American Academy of Pediatrics establishes the foundational dosing for pediatric patients:
- Divided dosing: 15-22.5 mg/kg/day given every 8 hours (5-7.5 mg/kg per dose) 1, 2
- Once-daily dosing: 15-20 mg/kg/day as a single daily dose 2, 1
- The FDA label confirms 15 mg/kg/day divided into 2-3 equal doses (7.5 mg/kg every 12 hours or 5 mg/kg every 8 hours) for children with normal renal function 3
Practical Dosing Example
For a typical 3-year-old weighing approximately 14-15 kg:
- Every 8-hour dosing: 70-112.5 mg per dose (5-7.5 mg/kg) 1
- Once-daily dosing: 210-300 mg as a single dose (15-20 mg/kg) 2, 1
Once-Daily vs. Divided Dosing
Once-daily dosing is increasingly preferred and may offer superior outcomes:
- A randomized trial in critically ill pediatric patients demonstrated 83% clinical cure with once-daily (20 mg/kg) versus 66% with twice-daily dosing (P=0.001), with significantly less nephrotoxicity (21% vs 35%, P=0.05) 4
- Another pediatric study using 20 mg/kg once daily achieved 98% satisfactory clinical results with no detected nephrotoxicity or ototoxicity 5
- The divided dosing approach (7.5 mg/kg every 12 hours) has been validated with appropriate pharmacokinetics and no accumulation after 4 days of treatment 6
Critical Monitoring Requirements
The American Academy of Pediatrics mandates specific therapeutic drug monitoring:
- Peak levels: Measure 30-90 minutes after infusion, targeting 30-40 mg/L for once-daily dosing 1
- Trough levels: Measure just prior to next dose, must remain <5 mg/L to prevent toxicity 7
- Peak levels above 35 mcg/mL and trough levels above 10 mcg/mL should be avoided 3
Duration and Safety Considerations
- Treatment duration: 7-10 days is standard; reassess if therapy extends beyond 10 days 3, 7
- Baseline assessment: Obtain audiogram, vestibular testing, and serum creatinine before initiating therapy 7
- Ongoing monitoring: Monthly renal function assessment and auditory/vestibular symptom screening 7
- Ototoxicity occurs in 1.5-24% of patients, with higher rates in longer courses 7
Common Pitfalls to Avoid
- Never use fixed 500 mg doses regardless of weight in pediatric patients—this ignores weight-based dosing principles and risks treatment failure 1
- Do not reduce the milligram dose in renal impairment; instead extend the dosing interval 7
- In very small infants, recommended doses often produce excessive levels, emphasizing the critical need for therapeutic drug monitoring 8