What is the first-line antibiotic treatment for an adult with a bacterial sore throat?

First-Line Antibiotic Treatment for Adult Bacterial Sore Throat

Penicillin V, taken twice or three times daily for 10 days, is the first-line antibiotic treatment for adults with bacterial sore throat. 1

Diagnosis Before Treatment

Before initiating antibiotic therapy, proper diagnosis is essential:

• Use Centor criteria to assess likelihood of Group A β-hemolytic streptococcal (GABHS) infection:

  • Fever history
  • Tonsillar exudates
  • No cough
  • Tender anterior cervical lymphadenopathy

• Testing recommendations:

  • Patients with 0-1 criteria: No testing or antibiotics needed
  • Patients with 2-4 criteria: Perform rapid antigen detection test (RADT) and/or throat culture
  • Only treat with antibiotics if GABHS is confirmed 1, 2

First-Line Antibiotic Treatment

When GABHS is confirmed:

• First choice: Penicillin V

  • Adult dosing: 500 mg twice daily for 10 days 1, 3
  • Full 10-day course is recommended to ensure bacterial eradication and prevent complications 1

• Rationale for penicillin V as first choice:

  • Proven efficacy and safety
  • Narrow spectrum (targeted therapy)
  • Low cost
  • No development of resistance over decades 1
  • Prevents complications like acute rheumatic fever 1

Alternative Antibiotics (for penicillin allergy)

• For non-anaphylactic penicillin allergy:

  • First-generation cephalosporins 4

• For anaphylactic penicillin allergy:

  • Erythromycin 2
  • Clindamycin 3
  • Azithromycin (note: increasing resistance in some regions) 3, 4

Important Clinical Considerations

1. Modest benefit of antibiotics: Antibiotics shorten duration of symptoms by only 1-2 days; the number needed to treat to reduce symptoms is 6 after 3 days of treatment 1

2. Avoid unnecessary prescribing: Despite most sore throats being viral, over 60% of adults with sore throat receive antibiotics 1, 5

3. Avoid broader-spectrum antibiotics: There has been a concerning trend of increased use of non-recommended, broader-spectrum antibiotics like extended-spectrum macrolides and fluoroquinolones 5

4. Symptomatic treatment: All patients should be offered analgesics (ibuprofen or paracetamol) for pain relief 1

5. Treatment failure: Patients with worsening symptoms after antibiotic initiation or symptoms lasting 5+ days after starting treatment should be reevaluated 4

Common Pitfalls to Avoid

• Prescribing antibiotics without confirming GABHS infection
• Using broader-spectrum antibiotics as first-line therapy
• Shortening the standard 10-day penicillin therapy
• Using macrolides as first-line therapy due to increasing resistance
• Treating asymptomatic carriers of GABHS
• Prescribing antibiotics for viral pharyngitis (most cases)

Despite some studies suggesting cephalosporins may have slightly better clinical cure rates than penicillin, the differences are small and not clinically relevant. The ecological risks of using broader-spectrum antibiotics and the proven track record of penicillin in preventing complications like rheumatic fever strongly support maintaining penicillin V as the first-line treatment 1, 6.