What is the recommended antibiotic for an adult with strep throat and an ear infection?

Antibiotic Treatment for Strep Throat and Ear Infection in Adults

For an adult with both strep throat and an ear infection, amoxicillin 500 mg twice daily for 10 days is the recommended first-line treatment, as it effectively covers both Group A Streptococcus pharyngitis and the typical bacterial pathogens causing acute otitis media (Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis). 1, 2, 3

First-Line Treatment Approach

Amoxicillin is the preferred single agent because:

• It provides strong, high-quality evidence-based coverage for Group A Streptococcus with a narrow spectrum of activity 1
• It covers the primary bacterial pathogens in adult acute otitis media (S. pneumoniae, H. influenzae, M. catarrhalis) 2, 4, 3
• The standard adult dosing is 500 mg twice daily for 10 days, which addresses both infections simultaneously 1
• It has proven efficacy, safety, and low cost compared to alternatives 1

When to Consider Amoxicillin-Clavulanate Instead

Upgrade to amoxicillin-clavulanate (1.75 g/250 mg per day) if:

• The patient has had recent antibiotic exposure within the past month 2, 4
• There is concern for beta-lactamase-producing organisms 2, 4
• The ear infection appears moderate to severe 2

Amoxicillin-clavulanate provides 90-92% clinical efficacy for acute otitis media in adults and covers beta-lactamase-producing strains of H. influenzae and M. catarrhalis 2, 4

Treatment for Penicillin-Allergic Patients

For patients with non-anaphylactic penicillin allergy:

• First-generation cephalosporins (cephalexin 500 mg twice daily for 10 days) are appropriate for strep throat 1
• However, avoid cephalosporins in patients with immediate hypersensitivity reactions 1

For patients with true penicillin allergy (including anaphylaxis):

• Respiratory fluoroquinolones (levofloxacin 500-750 mg once daily or moxifloxacin) provide 90-92% efficacy for otitis media and cover strep throat 2, 4
• Alternative: Clindamycin 300 mg three times daily for 10 days covers strep throat but has limited coverage for H. influenzae 1

Avoid azithromycin as monotherapy despite its convenience, as it has significant limitations with 20-25% bacteriologic failure rates for otitis media and increasing resistance in strep throat (varies geographically) 1, 2

Critical Diagnostic Considerations

Before prescribing antibiotics, confirm:

• Strep throat diagnosis with rapid antigen detection test (RADT) or throat culture in adults 1
• Ear infection diagnosis requires visualization of the tympanic membrane showing signs of acute otitis media (bulging, erythema, effusion) 2, 4
• Do not prescribe antibiotics for isolated tympanic membrane redness with normal landmarks 4

Monitoring and Treatment Failure

Reassess the patient if:

• No improvement occurs within 48-72 hours of starting antibiotics 2, 4
• Symptoms worsen after appropriate antibiotic initiation 5
• Symptoms persist beyond 5 days of treatment 5

If treatment fails:

• Switch to a different antibiotic class rather than increasing the dose 2
• For confirmed treatment failure with amoxicillin, consider amoxicillin-clavulanate or a respiratory fluoroquinolone 2, 4
• Do not continue the same antibiotic beyond 72 hours without improvement 2

Adjunctive Symptomatic Treatment

Pain management is essential:

• Offer systemic analgesics (acetaminophen or ibuprofen) to all patients for both throat and ear pain 1, 2
• Analgesics are especially important during the first 24 hours 2
• Throat lozenges may provide additional relief for pharyngitis 1
• Corticosteroids are not routinely recommended for strep throat 1

Common Pitfalls to Avoid

Do not:

• Prescribe antibiotics without confirming bacterial infection (strep test for throat, proper visualization for ear) 1, 4
• Use azithromycin as first-line therapy due to high failure rates and resistance 1, 2
• Continue ineffective antibiotics beyond 72 hours without reassessment 2
• Treat chronic Group A Streptococcus carriers routinely, as they are at low risk for complications 1
• Prescribe systemic antibiotics for uncomplicated otitis externa (swimmer's ear), which requires topical therapy 2