What is the recommended dosage of amoxicillin for mild to moderate infections?

Amoxicillin Dosage for Mild to Moderate Infections

For adults with mild to moderate infections, amoxicillin 500 mg every 12 hours or 250 mg every 8 hours is the standard dosing regimen, while children ≥3 months and <40 kg should receive 25 mg/kg/day divided every 12 hours or 20 mg/kg/day divided every 8 hours. 1

Adult Dosing

Standard dosing for mild to moderate infections:

• 250 mg every 8 hours OR 500 mg every 12 hours for ear/nose/throat, skin/skin structure, and genitourinary tract infections 1
• For severe infections or lower respiratory tract infections: 875 mg every 12 hours or 500 mg every 8 hours 1
• Maximum dose should not exceed 4000 mg/day 2

Infection-specific dosing:

• Dental/tooth infections: 500 mg three times daily for 7-10 days 3
• Acute bacterial rhinosinusitis: 1.5-4 g/day (lower doses for mild disease without recent antibiotic use, higher doses for areas with high penicillin-resistant S. pneumoniae prevalence) 2
• Community-acquired pneumonia: 50-75 mg/kg/day in 2 doses (for Streptococcus pneumoniae) 2

Pediatric Dosing (≥3 months and <40 kg)

Mild to moderate infections:

• 25 mg/kg/day divided every 12 hours OR 20 mg/kg/day divided every 8 hours 2, 1

Severe infections or lower respiratory tract infections:

• 45 mg/kg/day divided every 12 hours OR 40 mg/kg/day divided every 8 hours 1

Skin infections (children ≥3 months and <40 kg):

• 25 mg/kg/day every 12 hours OR 20 mg/kg/day every 8 hours 2

Acute bacterial rhinosinusitis (high-dose regimen for resistant organisms):

• 90 mg/kg/day for children at risk for penicillin-resistant S. pneumoniae 2

Community-acquired pneumonia:

• 75-100 mg/kg/day in 3 doses if β-lactamase negative H. influenzae 2

Infants <3 months (12 weeks)

• Maximum 30 mg/kg/day divided every 12 hours due to incompletely developed renal function 1
• No dosing recommendations exist for pediatric patients with impaired renal function in this age group 1

Renal Impairment Dosing

For adults and children >40 kg with severe renal impairment:

• GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours 1
• GFR <10 mL/min: 500 mg or 250 mg every 24 hours 1
• Hemodialysis: 500 mg or 250 mg every 24 hours, with additional dose during and at end of dialysis 1
• Patients with GFR <30 mL/min should NOT receive the 875 mg dose 1

Critical Administration Details

Timing and duration:

• Take at the start of a meal to minimize gastrointestinal intolerance 1
• Continue treatment for minimum 48-72 hours beyond symptom resolution or evidence of bacterial eradication 1
• For Streptococcus pyogenes infections: minimum 10 days to prevent acute rheumatic fever 1

Common pitfalls to avoid:

• The 875 mg dose should be avoided in patients with severe renal impairment (GFR <30 mL/min) 1
• Renal dosing adjustment is required for patients with significant renal dysfunction 2
• For dental abscesses, antibiotics alone are insufficient—surgical intervention (drainage, extraction, or root canal) is necessary and should not be delayed 3

Special Populations

Pregnancy:

• Category B—compatible with use during pregnancy 2

Breastfeeding:

• Minimal risk to infant, compatible with breastfeeding 2
• Distributed into milk, use with caution 2