What is the recommended dosage of amoxicillin (amoxicillin) syrup for a 1-year-old patient weighing 9kg?

Amoxicillin Dosing for a 1-Year-Old Weighing 9kg

For a 1-year-old child weighing 9kg, the recommended amoxicillin dose depends on the indication: for mild to moderate infections (such as ear/nose/throat or skin infections), give 45 mg/kg/day divided into 2 doses (approximately 200mg or 4 mL of 125mg/5mL suspension twice daily), while for severe infections or pneumonia, give 90 mg/kg/day divided into 2 doses (approximately 400mg or 8 mL of 125mg/5mL suspension twice daily). 1, 2

Standard Dosing by Severity

Mild to Moderate Infections

• For common uncomplicated infections (ear/nose/throat, skin, genitourinary), the American Academy of Pediatrics recommends 45 mg/kg/day divided every 12 hours 1, 2
• For a 9kg child, this equals approximately 200mg per dose (4 mL of 125mg/5mL suspension) given twice daily 1
• This dosing is appropriate for most routine bacterial infections in fully immunized children 1

Severe Infections or High-Resistance Areas

• For severe infections, pneumonia, or areas with high pneumococcal resistance, the Infectious Diseases Society of America recommends 90 mg/kg/day divided every 12 hours 1, 2
• For a 9kg child, this equals approximately 400mg per dose (8 mL of 125mg/5mL suspension) given twice daily 1
• The higher dose of 90 mg/kg/day is essential to overcome pneumococcal resistance, and underdosing with 40-45 mg/kg/day is a common and dangerous error 2

FDA-Approved Dosing Guidelines

• The FDA label confirms that for children aged 3 months and older weighing less than 40kg, mild/moderate infections require 25 mg/kg/day in divided doses every 12 hours or 20 mg/kg/day in divided doses every 8 hours 3
• For severe infections or lower respiratory tract infections, the FDA recommends 45 mg/kg/day in divided doses every 12 hours or 40 mg/kg/day in divided doses every 8 hours 3
• The twice-daily dosing regimen improves compliance compared to three-times-daily dosing 1, 4

Administration Instructions

• Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance 3
• After reconstitution, shake the oral suspension well before each use 3
• The suspension can be placed directly on the child's tongue or mixed with formula, milk, fruit juice, or water, and should be taken immediately 3
• Refrigeration is preferable but not required; discard any unused portion after 14 days 3

Treatment Duration and Monitoring

• Treatment should continue for a minimum of 48-72 hours beyond symptom resolution 3
• For Streptococcus pyogenes infections (such as strep throat or scarlet fever), at least 10 days of treatment is mandatory to prevent acute rheumatic fever 1, 3
• For pneumonia, the standard treatment duration is 10 days 1, 2
• Children on appropriate therapy should demonstrate clinical improvement within 48-72 hours; if no improvement occurs, reevaluation and further investigation are necessary 1, 2, 5

Critical Considerations

• The current recommendation of 40 mg/kg/day is inadequate to effectively eradicate resistant Streptococcus pneumoniae, particularly during viral coinfection 6
• Research demonstrates that amoxicillin middle ear fluid penetration is lower in children with viral coinfection, supporting the need for higher dosing in these scenarios 6
• For Group A Streptococcal infections, the American Heart Association recommends 50-75 mg/kg/day divided into 2 doses for 10 days, not exceeding 1000 mg per dose 1

Common Pitfalls to Avoid

• Underdosing at 40-45 mg/kg/day for serious infections is a dangerous error that fails to achieve adequate coverage against resistant organisms 2
• Failing to complete the full 10-day course for streptococcal infections increases the risk of rheumatic fever 1, 3
• Not adjusting dosing based on infection severity and local resistance patterns can lead to treatment failure 1, 2