When to Use Antibiotics for a Sore Throat: Clear Guidance & Risks

Antibiotics are a class of medicines that kill or inhibit bacterial growth, typically prescribed in doses measured in milligrams per kilogram. They work by targeting bacterial cell walls, protein synthesis, or DNA replication, with common examples including penicillin and amoxicillin. A sore throat feels like a simple annoyance, but the underlying cause can be viral or bacterial. Knowing the difference is the key to deciding whether antibiotics are warranted.

What Really Causes a Sore Throat?

Most sore throats (about 70‑80%) are viral. Rhinoviruses, influenza, and coronavirus variants irritate the lining of the pharynx, leading to pain, redness, and sometimes fever. Viral infections resolve on their own within a week, and antibiotics do nothing against them.

About 10‑15% of cases are bacterial, with Streptococcus pyogenes (GroupAstrep) being the most common culprit. This bacterium can cause acute pharyngitis, an inflammation of the throat, and may lead to complications like rheumatic fever if left untreated.

Other bacterial agents-Staphylococcus aureus, Neisseria gonorrhoeae-are rare but still possible, especially in immunocompromised patients.

When Are Antibiotics Appropriate?

Doctors rely on a combination of clinical signs and rapid tests to decide. The Centor criteria is a five‑point scoring system that looks at:

1. Fever over 38°C (100.4°F)
2. Absence of cough
3. Swollen, tender anterior cervical lymph nodes
4. Presence of tonsillar exudates
5. Age (younger patients score higher)

A score of 3 or more usually triggers a rapid antigen detection test (RADT). This point‑of‑care test delivers results in minutes and has a specificity >95%, meaning a positive result reliably indicates Strep infection.

If the RADT is negative but the clinical suspicion remains high, a throat culture-grown on blood agar and read after 24‑48hours-offers the definitive answer.

First‑Line Antibiotics for Strep Throat

The two most frequently prescribed drugs are penicillin and amoxicillin. Below is a quick comparison.

Both drugs achieve >95% cure rates when taken as directed. In penicillin‑allergic patients, macrolides like azithromycin are alternatives, though they carry a higher risk of fostering resistance.

The Hidden Costs of Unnecessary Antibiotics

When antibiotics are given for viral sore throats, they add no benefit and can cause harm. Key concerns include:

• Antibiotic resistance - bacteria evolve mechanisms (e.g., beta‑lactamase production) that render drugs ineffective. In Australia, resistance rates for common pathogens have risen by 20% over the past decade.
• Side effects such as nausea, diarrhea, and, in rare cases, Clostridioides difficile infection, which can be life‑threatening.
• Disruption of the normal microbiome, leading to issues like yeast overgrowth or reduced immunity.

Health authorities-including the World Health Organization (WHO) and Australia’s Therapeutic Goods Administration (TGA)-recommend prescribing antibiotics only when a bacterial cause is confirmed or highly probable.

Diagnosing Correctly: Tools and Decision Flow

Below is a practical flow that mirrors what many GP clinics follow:

1. Assess symptoms and apply the Centor criteria.
2. If score≥3, perform a rapid antigen detection test.
3. Positive→prescribe penicillin or amoxicillin.
   • Educate patient on adherence (complete the 10‑day course).
4. Negative→consider throat culture if clinical suspicion remains high.
5. If culture positive→same antibiotic regimen.
6. If still negative→manage symptomatically with analgesics and hydration.

This algorithm minimizes unnecessary drug exposure while ensuring bacterial infections receive prompt treatment.

Non‑Antibiotic Strategies for Symptom Relief

Even when antibiotics aren’t needed, patients still want relief. Effective measures include:

• Over‑the‑counter analgesics: ibuprofen 200-400mg every 6h (max 1,200mg/day) or paracetamol 500-1,000mg every 4-6h (max 4g/day).
• Warm saline gargles (½tsp salt in 240ml water) 3-4 times daily.
• Honey‑lemon tea for soothing and mild antimicrobial action (avoid for children <1year).
• Humidified air to keep mucous membranes moist.

These approaches address pain and inflammation without contributing to resistance.

Practical Checklist for Patients

• Note any fever, cough, or swollen glands.
• Count how many of the Centor criteria you meet.
• Ask your clinician about a rapid antigen test if you score 3 or higher.
• If prescribed antibiotics, take the full course even if you feel better.
• Use ibuprofen or paracetamol for pain, and stay hydrated.
• Seek medical attention if you develop a rash, difficulty breathing, or symptoms persist beyond 7days.

Future Directions: Antimicrobial Stewardship in Primary Care

Australia’s National Antimicrobial Stewardship Program (NASP) aims to cut unnecessary prescriptions by 20% over the next five years. Strategies include:

• Electronic decision‑support prompts in GP software.
• Patient‑facing education sheets that explain why antibiotics may not help.
• Audit and feedback loops for prescribers.

When clinicians and patients collaborate, the balance shifts toward smarter use of antibiotics, preserving their effectiveness for serious bacterial infections.