Azithromycin Dosing for a 16kg Child
For a 16kg child using azithromycin 200mg/5mL suspension, administer 4 mL (160mg) as the initial dose on Day 1.
Dosing Calculation
The standard pediatric dosing for azithromycin in children >6 months is 10 mg/kg on Day 1, followed by 5 mg/kg daily on Days 2-5 1, 2.
For this 16kg child:
- Day 1 dose: 10 mg/kg × 16 kg = 160 mg
- Days 2-5 dose: 5 mg/kg × 16 kg = 80 mg daily
Volume Administration
Using the 200mg/5mL suspension (concentration = 40 mg/mL):
- Day 1: 160 mg ÷ 40 mg/mL = 4 mL
- Days 2-5: 80 mg ÷ 40 mg/mL = 2 mL daily
This is confirmed by the FDA dosing table for the 5-day regimen, which specifies that a 20kg child (the closest weight bracket) receives 5 mL on Day 1 and 2.5 mL on Days 2-5 using the 200mg/5mL formulation 2. Your 16kg patient falls proportionally between the 10kg and 20kg brackets, making 4 mL appropriate.
Important Considerations
Maximum dose limits: The Day 1 dose should not exceed 500 mg, and subsequent daily doses should not exceed 250 mg 1, 2. At 16kg, this child is well below these thresholds.
Administration: Azithromycin suspension can be given with or without food 2.
Common pitfall: Do not confuse the different dosing regimens. The 3-day regimen uses 10 mg/kg daily for all 3 days, while the 5-day regimen uses the loading dose approach described above 2. For most indications in children >6 months (community-acquired pneumonia, pharyngitis), the 5-day regimen with loading dose is standard 1, 3.