What is the recommended dose of amoxicillin (amoxicillin) for the treatment of otitis media?

Amoxicillin Dosing for Acute Otitis Media

For children with acute otitis media, use high-dose amoxicillin at 80-90 mg/kg/day divided into 2 doses for 10 days; for adults, use 1500-4000 mg/day divided into 2-3 doses. 1

Pediatric Dosing Algorithm

Standard First-Line Therapy

• High-dose amoxicillin 80-90 mg/kg/day divided twice daily is the recommended first-line treatment for most children with acute otitis media who have not received amoxicillin in the past 30 days, do not have concurrent purulent conjunctivitis, and are not allergic to penicillin 2, 1
• Treatment duration is 10 days for children under 2 years of age 2, 3
• For children over 2 years with uncomplicated cases, 5-7 days may be acceptable 2, 1

Pharmacologic Rationale for High-Dose Therapy

• High-dose amoxicillin (80-90 mg/kg/day) achieves middle ear fluid concentrations exceeding the minimum inhibitory concentration (MIC) for penicillin-resistant Streptococcus pneumoniae strains with amoxicillin MIC ≤2.0 μg/mL 1, 4
• This dosing achieves 92% bacteriologic eradication of S. pneumoniae (including penicillin-nonsusceptible strains), 84% eradication of beta-lactamase-negative H. influenzae, and 62% eradication of beta-lactamase-positive H. influenzae 2, 4
• Standard-dose amoxicillin (40 mg/kg/day) is inadequate for resistant organisms, particularly during viral coinfection 5

When to Use Amoxicillin-Clavulanate Instead

Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate, divided twice daily) in these specific scenarios: 1

• Amoxicillin use within the previous 30 days 2, 1
• Concurrent purulent conjunctivitis 2, 1
• Treatment failure after 48-72 hours of amoxicillin therapy 1, 6
• Recurrent AOM unresponsive to amoxicillin 2

Neonates and Young Infants

• For neonates and infants under 12 weeks (3 months): use 30 mg/kg/day divided every 12 hours 3
• The 125 mg/5 mL oral suspension formulation is recommended for this age group 3

Adult Dosing Algorithm

Standard Adult Dosing

• Adults should receive 1500-4000 mg/day of amoxicillin divided into 2-3 doses 1
• Standard-risk adults with no recent antibiotic use: 1500 mg/day (500 mg three times daily or 750 mg twice daily) 1
• High-risk patients or those with recent antibiotic exposure (within 4-6 weeks): 4000 mg/day 1

Preferred First-Line for Adults

• Amoxicillin-clavulanate is actually the preferred first-line agent for adults because it provides coverage against beta-lactamase-producing organisms (H. influenzae and M. catarrhalis), which cause 17-34% and 100% of treatment failures respectively 2
• The standard adult dose of amoxicillin-clavulanate is 3000 mg/day (875 mg/125 mg twice daily or 500 mg/125 mg three times daily) 2, 3
• For more severe respiratory tract infections, use 875 mg/125 mg every 12 hours 3

Critical Monitoring and Treatment Failure

Reassessment Timeline

• Reassess patients at 48-72 hours if symptoms worsen or fail to improve 1, 6
• Treatment failure is defined as: worsening condition, persistence of symptoms beyond 48 hours after antibiotic initiation, or recurrence within 4 days of treatment discontinuation 2

Second-Line Options After Failure

• Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day for children; 875 mg/125 mg twice daily for adults) 2, 1
• Alternative: ceftriaxone 50 mg/kg IM for 3 days 2, 6

Penicillin Allergy Alternatives

Non-Type I Hypersensitivity

For patients with non-type I penicillin allergy (no anaphylaxis, angioedema, or urticaria): 6

• Cefdinir: 14 mg/kg/day in 1-2 doses (pediatric) or 300 mg twice daily (adult) 1, 6
• Cefuroxime: 30 mg/kg/day in 2 divided doses (pediatric) or 500 mg twice daily (adult) 1, 6
• Cefpodoxime: 10 mg/kg/day in 2 divided doses (pediatric) 1, 6

Cross-Reactivity Considerations

• Cross-reactivity between penicillins and second/third-generation cephalosporins is negligible due to distinct chemical structures 6
• First-generation cephalosporins have higher cross-reactivity and should be avoided 6

Common Pitfalls to Avoid

Dosing Errors in Obese Children

• In children weighing >20 kg, physicians frequently underdose amoxicillin, prescribing significantly lower than the recommended 80-90 mg/kg/day 7
• Do not automatically cap pediatric doses at the standard adult dose of 1500 mg/day—children requiring higher weight-based doses should receive them 7
• For children weighing ≥40 kg, dose according to adult recommendations 3

Formulation Substitution Errors

• Never substitute two 250 mg/125 mg tablets for one 500 mg/125 mg tablet—they contain different amounts of clavulanic acid (250 mg total vs. 125 mg) 3
• The 250 mg/125 mg tablet and 250 mg/62.5 mg chewable tablet are not interchangeable 3

Inappropriate Antibiotic Selection

• Plain amoxicillin fails in 62% of beta-lactamase-positive H. influenzae infections, which represent the predominant cause of treatment failure 4
• Beta-lactamase-producing organisms (H. influenzae and M. catarrhalis) account for the majority of bacteriologic failures with amoxicillin monotherapy 4

Pain Management

• Address pain immediately with oral analgesics (acetaminophen or ibuprofen) regardless of antibiotic decision, especially during the first 24 hours 2, 6
• NSAIDs at anti-inflammatory doses and corticosteroids have not demonstrated efficacy for AOM treatment 2