What is the appropriate dose of amoxicillin (amoxicillin) for an 11-month-old infant with cough, fever, and colds, using the 250mg/5ml concentration?

Amoxicillin Dosing for an 11-Month-Old Infant with Respiratory Infection

For an 11-month-old infant with cough, fever, and colds, give amoxicillin 45 mg/kg/day divided into 2 doses (every 12 hours) using the 250mg/5ml suspension. 1

Calculating the Specific Dose

To determine the exact volume to administer, you need to:

• Weigh the infant to calculate the precise dose based on 45 mg/kg/day 1
• Divide the total daily dose by 2 to get the amount per dose (given every 12 hours) 1
• Convert to milliliters using the 250mg/5ml concentration 2

Example Calculation:

• For a typical 11-month-old weighing approximately 9-10 kg:
  • Total daily dose = 45 mg/kg × 9 kg = 405 mg/day 1
  • Per dose = 405 mg ÷ 2 = 202.5 mg per dose 1
  • Volume = (202.5 mg ÷ 250 mg) × 5 ml = approximately 4 ml twice daily 1, 2

Dosing Rationale

• The American Academy of Pediatrics and Infectious Diseases Society of America recommend 45 mg/kg/day in 2 doses for mild to moderate respiratory tract infections in infants over 3 months of age 1
• This dosing provides adequate coverage for common respiratory pathogens including Streptococcus pneumoniae and Haemophilus influenzae (β-lactamase negative strains) 1, 2
• The twice-daily dosing improves adherence compared to three-times-daily regimens 1

When to Consider Higher Dosing

Increase to 90 mg/kg/day divided into 2 doses if: 1

• The infection is severe (high fever, respiratory distress, toxic appearance) 1
• You practice in an area with high pneumococcal resistance 1
• The infant fails to improve within 48-72 hours on standard dosing 1

For the same 9 kg infant, this would be approximately 8 ml twice daily 1

Treatment Duration and Monitoring

• Continue treatment for 7-10 days for most respiratory infections 1
• The infant should show clinical improvement within 48-72 hours; if not, reevaluation is necessary 1
• Complete the full course even if symptoms resolve earlier 1

Administration Instructions

• Give at the start of a meal to minimize gastrointestinal side effects 2
• Shake the suspension well before each use 2
• The suspension can be mixed with formula, milk, or juice if needed, but must be taken immediately after mixing 2
• Store reconstituted suspension in refrigerator (preferred but not required) and discard after 14 days 2

Important Caveats

• This dosing assumes the infection is caused by susceptible bacteria (β-lactamase negative organisms) 2
• If the infant has received inadequate Haemophilus influenzae type b vaccination or has concurrent purulent otitis media, consider amoxicillin-clavulanate instead 1
• Watch for common adverse effects including diarrhea, nausea, and rash 1
• Do not use this dosing for infants under 3 months of age, who require different dosing due to immature renal function 2, 3