What is a suitable antibiotic for an upper respiratory infection (URI)?

Antibiotics Are NOT Recommended for Most Upper Respiratory Infections

Most upper respiratory infections (URIs) are viral (90% of cases) and should be managed with supportive care alone—antibiotics are not indicated and cause more harm than benefit. 1, 2

When Antibiotics Are Absolutely NOT Indicated

The following conditions should never receive antibiotics:

• Common cold - purely viral, resolves spontaneously within 7-10 days 1, 3
• Acute bronchitis in otherwise healthy adults - no antibiotics needed even with fever present 2, 3
• Influenza - antiviral agents only if indicated, not antibiotics 3
• COVID-19 - unless secondary bacterial infection documented 3
• Laryngitis - viral etiology 3, 4
• Nonspecific URI/acute rhinopharyngitis - antibiotic treatment does not enhance resolution 5

Critical pitfall: Purulent nasal discharge or sputum does NOT indicate bacterial infection and does NOT justify antibiotic use in uncomplicated URI. 5

When Antibiotics ARE Indicated

Antibiotics should only be prescribed for these specific bacterial complications:

1. Acute Bacterial Rhinosinusitis

Only when meeting specific criteria 1, 2:

• Symptoms persisting >10 days without improvement, OR
• Severe symptoms: fever >39°C with purulent nasal discharge for ≥3 consecutive days, OR
• "Double sickening": worsening after initial improvement following typical viral URI

First-line antibiotic: Amoxicillin-clavulanate 1, 2

• Dosing: 90 mg/6.4 mg per kg per day (high-dose formulation) 6
• Duration: 5-8 days for uncomplicated cases 6

2. Acute Otitis Media (AOM)

When stringent diagnostic criteria are met 7, 6:

First-line antibiotic: Amoxicillin 6, 8

• Mild-moderate infections: 45 mg/kg/day divided twice daily 6
• Severe infections or drug-resistant pathogens: 90 mg/kg/day 6
• Duration: 5 days for uncomplicated cases in children >2 years; 10 days for children <2 years 6

Consider amoxicillin-clavulanate if: 6

• Recent antibiotic exposure (within 4-6 weeks)
• Known high local prevalence of amoxicillin-resistant H. influenzae
• Insufficient vaccination against H. influenzae type b
• Severe symptoms at presentation

3. Group A Streptococcal Pharyngitis

Only when confirmed by rapid antigen test or culture 7:

First-line antibiotic: Amoxicillin 2

Recommended Supportive Care (First-Line for Viral URI)

All patients with viral URI should receive: 2

• Analgesics (acetaminophen, NSAIDs) for pain relief
• Antipyretics for fever control
• Saline nasal irrigation
• Intranasal corticosteroids for symptom relief
• Systemic or topical decongestants as needed

Inhaled ipratropium bromide may help suppress cough in URI or chronic bronchitis 1

Critical Clinical Decision Points

Reassess after 48-72 hours of antibiotic therapy if prescribed 6:

• Fever should resolve within 24 hours for pneumococcal infections, 2-4 days for other bacteria 2
• Lack of improvement indicates treatment failure—consider alternative diagnosis or resistant pathogen 6

Warning signs requiring immediate reassessment: 1

• High fever (≥38.5°C) persisting >3 days suggests bacterial complication
• Severe unilateral facial pain, especially worsening when bending forward
• Signs of complications (periorbital edema, altered mental status)

Antibiotics to AVOID for Respiratory Infections

Never use first-generation cephalosporins (e.g., cephalexin) for respiratory infections due to inadequate activity against penicillin-resistant S. pneumoniae 2

Avoid macrolides and oral third-generation cephalosporins as first-line agents due to high rates of pneumococcal resistance 6

The Harm of Inappropriate Antibiotic Use

Prescribing antibiotics for viral URI causes: 7, 6

• Adverse events ranging from diarrhea and rash to Stevens-Johnson syndrome and anaphylaxis
• Disruption of the microbiome, potentially contributing to inflammatory bowel disease, obesity, eczema, and asthma in children
• Increased antibiotic resistance in individuals and communities
• Unnecessary medical costs

The judicious approach prioritizes determining the likelihood of bacterial infection before prescribing, weighing benefits against harms, and implementing evidence-based prescribing strategies. 7