What are the best antibiotics for an ongoing sore throat suspected to be of bacterial origin in adults?

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Last updated: January 26, 2026View editorial policy

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Best Antibiotics for Ongoing Sore Throat

Penicillin V (phenoxymethylpenicillin), given twice or three times daily for 10 days, remains the first-choice antibiotic for bacterial pharyngitis, with amoxicillin as an acceptable alternative in younger children due to taste and formulation considerations. 1, 2

When Antibiotics Are Actually Indicated

Before prescribing any antibiotic, you must first determine if antibiotics are warranted at all:

  • Do NOT prescribe antibiotics for patients with 0-2 Centor criteria (low probability of Group A Streptococcus), as these cases are predominantly viral and antibiotics provide no meaningful benefit 1, 2

  • For patients with 3-4 Centor criteria, consider rapid antigen testing before prescribing, and discuss with patients that antibiotic benefits are modest—shortening symptoms by only 1-2 days 1, 2

  • Most sore throats (>65%) are viral and resolve within one week without antibiotics 2, 3

First-Line Antibiotic Choice

Penicillin V is the gold standard for the following reasons:

  • Group A β-hemolytic streptococci have shown zero resistance to penicillin over five decades of use 1
  • Proven efficacy in preventing serious complications (rheumatic fever, peritonsillar abscess) 1
  • Narrow spectrum minimizes disruption to normal flora and reduces selection pressure for resistance 1, 4
  • Lowest cost option 1

Dosing: Penicillin V 250-500 mg twice or three times daily for 10 days 1, 2, 5

Alternative First-Line Options

Amoxicillin is an acceptable alternative, particularly in younger children:

  • Equivalent efficacy to penicillin V (clinical cure rates 86% vs 92% respectively) 1
  • Better palatability and available as suspension 1, 5
  • Critical caveat: Avoid amoxicillin in older children and adolescents due to risk of severe rash if Epstein-Barr virus infection is present 1

Second-Line Antibiotics

For penicillin allergy:

  • Cephalexin (first-generation cephalosporin) is preferred in regions with high macrolide resistance 1
  • Clarithromycin for patients with severe penicillin allergy, though this is a Watch-category antibiotic requiring judicious use 1

Important note on cephalosporins: While meta-analyses show cephalosporins have statistically superior bacteriological cure rates (OR 2.29-2.34), the clinical differences are not clinically meaningful and do not justify their routine use over penicillin 1

What NOT to Use

Avoid broad-spectrum antibiotics unless specifically indicated:

  • Extended-spectrum macrolides (azithromycin) show no superior efficacy compared to penicillin 1, 6
  • Fluoroquinolones are inappropriate for routine pharyngitis 7
  • In France, 8% of Group A Streptococcus strains are now resistant to macrolides, and 60% to tetracyclines 4
  • Broader-spectrum agents risk disrupting oropharyngeal ecology and promoting resistance 1, 4

Duration of Treatment

10 days remains the recommended duration for penicillin therapy:

  • Shorter courses (3-5 days) show inferior outcomes for symptom resolution 1
  • A 7-day course is superior to 3 days but still inferior to 10 days 1
  • The traditional 10-day regimen maximizes bacterial eradication, though the primary goal is now symptom relief rather than complication prevention in developed countries 1

Critical Pitfalls to Avoid

Do not prescribe antibiotics empirically without clinical assessment: Use Centor criteria (fever, tonsillar exudates, tender anterior cervical lymphadenopathy, absence of cough) to stratify risk 2, 3

Do not use erythema alone as justification: Pharyngeal erythema is present in both viral and bacterial pharyngitis and does not distinguish between them 8

For persistent sore throat (>2 weeks): This is atypical and demands evaluation for non-infectious causes (malignancy, GERD) rather than empiric antibiotics, as simple pharyngitis resolves within one week in >80% of cases 9

Delayed prescribing is a valid strategy: For patients with 3-4 Centor criteria, consider giving a prescription to fill only if symptoms worsen or fail to improve within 48 hours 1

Symptomatic Management

Always offer analgesics regardless of antibiotic use:

  • Ibuprofen or acetaminophen (paracetamol) are first-line for pain relief 2, 9
  • Exercise caution with NSAIDs in elderly patients due to cardiovascular, renal, and gastrointestinal risks 9

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Sore Throat Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

[Sore Throat - Guideline-based Diagnostics and Therapy].

ZFA. Zeitschrift fur Allgemeinmedizin, 2022

Guideline

Management of Erythematous, Non-Exudative Throat

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Persistent Sore Throat Evaluation and Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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