Can I prescribe amoxicillin (amoxicillin) again to a pediatric patient with a history of strep throat treated with amoxicillin 6 weeks ago, who now presents with strep throat and bilateral acute otitis media (AOM)?

Can You Prescribe Amoxicillin Again?

Yes, you can prescribe amoxicillin again for this patient with strep throat and bilateral AOM, since the previous amoxicillin course was completed more than 30 days ago (6 weeks). 1, 2

Treatment Algorithm Based on Timing of Prior Amoxicillin

The critical decision point is whether the last amoxicillin dose was within or beyond 30 days:

• If >30 days since last amoxicillin dose (your case): Use high-dose amoxicillin 80-90 mg/kg/day divided into 2-3 doses for 10 days as first-line therapy 1, 2
• If ≤30 days since last amoxicillin dose: Switch to amoxicillin-clavulanate (Augmentin) 90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate, using the 14:1 ratio formulation 3, 2

Why Amoxicillin Remains Appropriate at 6 Weeks

• The 30-day cutoff reflects the risk of recent antibiotic selection pressure for resistant organisms, particularly beta-lactamase-producing bacteria 2
• At 6 weeks post-treatment, the nasopharyngeal flora has typically returned to baseline, making amoxicillin-resistant organisms less likely 4
• High-dose amoxicillin achieves 92% eradication of Streptococcus pneumoniae (the primary pathogen in both strep pharyngitis and AOM) and 84% eradication of beta-lactamase-negative Haemophilus influenzae 1

Specific Dosing for Bilateral AOM

• Prescribe amoxicillin 80-90 mg/kg/day divided into 2 or 3 equal doses 1, 2
• Treatment duration: 10 days for children under 2 years with bilateral AOM 1, 2
• Maximum single dose is 2000 mg 3, 2
• Bilateral AOM requires immediate antibiotic therapy (not watchful waiting) due to higher treatment failure rates—21.7% with antibiotics versus 46.3% with placebo 2

Essential Pain Management

• Prescribe acetaminophen 15 mg/kg every 4-6 hours or ibuprofen 10 mg/kg every 6-8 hours immediately 2
• Pain control is mandatory regardless of antibiotic choice, as antibiotics provide no symptomatic relief in the first 24 hours 2

When to Switch to Augmentin

If the patient fails to improve or worsens at 48-72 hours:

• Switch to amoxicillin-clavulanate 90 mg/kg/day (14:1 ratio formulation) 1, 3, 2
• Treatment failure is most commonly caused by beta-lactamase-producing Haemophilus influenzae (62% failure rate with amoxicillin alone) 5
• If Augmentin fails, consider intramuscular ceftriaxone 50 mg/kg daily for 3 days 1

Critical Pitfalls to Avoid

• Do not use standard-dose amoxicillin (40-45 mg/kg/day) for bilateral AOM—high-dose is essential for eradicating penicillin-resistant Streptococcus pneumoniae 1, 5
• Do not prescribe trimethoprim-sulfamethoxazole or erythromycin-sulfisoxazole as second-line agents due to substantial pneumococcal resistance 1
• Do not routinely schedule a 10-14 day recheck unless the child has severe symptoms, recurrent AOM, or parental concerns—persistent middle ear effusion at 2 weeks (60-70% of cases) represents otitis media with effusion, not treatment failure 1
• Reassess at 48-72 hours only if symptoms fail to improve or worsen 1, 2

Adverse Event Considerations

• Amoxicillin causes adverse events (primarily diarrhea and rash) in approximately 5% more patients than placebo 6
• These adverse events are generally mild and do not outweigh the benefits in confirmed bilateral AOM 6
• Amoxicillin is responsible for a significant number of emergency department visits for medication-related adverse events in children, but serious reactions (Stevens-Johnson syndrome, anaphylaxis) remain rare 6