Best Antibiotic for Cough with Purulent Phlegm and Swollen Tonsils
Test for Group A Streptococcus first using rapid antigen detection test or throat culture, and only prescribe antibiotics if the test is positive—the preferred treatment is penicillin or amoxicillin for 10 days. 1
Clinical Assessment Algorithm
The presence of swollen tonsils suggests pharyngitis/tonsillitis, while cough with purulent phlegm creates diagnostic complexity that requires careful evaluation 1.
Key Diagnostic Distinction
The presence of cough actually argues AGAINST bacterial pharyngitis and suggests a viral etiology. 1 This is a critical pitfall—purulent sputum does NOT indicate bacterial infection, as purulence is due to inflammatory cells or sloughed mucosal epithelial cells, not bacteria 1.
Apply Modified Centor Criteria
Use the modified Centor criteria to determine likelihood of Group A Streptococcus 1:
- Fever by history
- Tonsillar exudates
- Tender anterior cervical adenopathy
- Absence of cough (your patient has cough, which counts against bacterial pharyngitis)
If fewer than 3 Centor criteria are met, do not test and do not prescribe antibiotics. 1
Rule Out Pneumonia
Before dismissing this as simple bronchitis, evaluate for pneumonia using clinical criteria 1:
- Tachycardia (heart rate >100 beats/min)
- Tachypnea (respiratory rate >24 breaths/min)
- Fever (oral temperature >38°C)
- Abnormal chest examination findings (rales, egophony, tactile fremitus)
If pneumonia is suspected based on these criteria, chest radiograph and different antibiotic approach are needed. 1
When Antibiotics Are NOT Indicated
Do not initiate antibiotic therapy for bronchitis with purulent sputum alone, even with cough—this is typically viral and antibiotics provide no benefit. 1 Antibiotics for acute bronchitis showed limited evidence of benefit and increased adverse events in systematic reviews 1.
When Antibiotics ARE Indicated
For Confirmed Group A Streptococcal Pharyngitis
If rapid antigen test or throat culture is positive for Group A Streptococcus:
First-line treatment: 1
- Penicillin (oral for 10 days) or intramuscular benzathine penicillin (single injection)
- Amoxicillin is equally effective and more palatable
For penicillin allergy: 1
- First-generation cephalosporins
- Erythromycin or other macrolides
Treatment duration should be 10 days to eradicate Group A Streptococcus from the pharynx. 1
For Community-Acquired Pneumonia (if confirmed)
If pneumonia is confirmed clinically or radiographically: 1
- Minimum 5 days of antibiotics
- Extension beyond 5 days should be guided by clinical stability (resolution of vital sign abnormalities, ability to eat, normal mentation)
- For outpatients without comorbidities: amoxicillin, doxycycline, or a macrolide 1
Critical Pitfalls to Avoid
Do not prescribe antibiotics based on purulent sputum color alone—green or yellow sputum does not signify bacterial infection 1
The combination of cough AND pharyngitis strongly suggests viral etiology—patients with sore throat plus cough, nasal congestion, conjunctivitis, or hoarseness are more likely viral and should not receive antibiotics 1
Do not use macrolides (azithromycin) for acute bronchitis—one study showed significantly more adverse events than placebo with no benefit 1
Watch for severe pharyngitis warning signs requiring urgent evaluation: difficulty swallowing, drooling, neck tenderness or swelling (concern for peritonsillar abscess, parapharyngeal abscess, epiglottitis, or Lemierre syndrome) 1
Symptomatic Management
Offer symptomatic relief regardless of antibiotic decision: 1
- Analgesics (aspirin, acetaminophen, NSAIDs)
- Throat lozenges
- Cough suppressants (dextromethorphan or codeine)
- First-generation antihistamines (diphenhydramine)
- Decongestants (phenylephrine)
Reassure patients that typical sore throat resolves in less than 1 week, and acute bronchitis is self-limited. 1