What is the recommended treatment for a patient with strep throat?

Treatment of Strep Throat

For patients with confirmed streptococcal pharyngitis, penicillin V (250 mg four times daily or 500 mg twice daily) or amoxicillin (50 mg/kg once daily, maximum 1000 mg) for a full 10 days remains the treatment of choice due to proven efficacy, narrow spectrum, safety profile, and low cost, with no documented penicillin resistance in Group A Streptococcus anywhere in the world. 1, 2, 3

Confirming the Diagnosis First

• Document Group A Streptococcus infection with either rapid antigen detection testing (RADT) or throat culture before initiating antibiotics, as clinical features alone cannot reliably distinguish bacterial from viral causes 2, 4
• A positive RADT is diagnostic and does not require backup culture 5
• After a negative RADT result, throat culture is recommended in children and adolescents 4

First-Line Antibiotic Regimens for Non-Allergic Patients

Adults and Adolescents

• Penicillin V: 250 mg four times daily OR 500 mg twice daily for 10 days 2, 6
• Amoxicillin: 500 mg every 12 hours or 250 mg every 8 hours for 10 days 3

Pediatric Patients (≥3 months and <40 kg)

• Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) for 10 days 2, 3
• Alternative dosing: 25 mg/kg/day divided every 12 hours or 20 mg/kg/day divided every 8 hours 3
• Amoxicillin is preferred over penicillin V in younger children due to better palatability and availability as suspension, with identical efficacy 1

Infants <3 Months

• Maximum dose: 30 mg/kg/day divided every 12 hours due to incompletely developed renal function 3

Treatment for Penicillin-Allergic Patients

Non-Immediate (Non-Anaphylactic) Penicillin Allergy

• First-generation cephalosporins are the preferred alternatives with strong, high-quality evidence 1, 2
• Cephalexin: 500 mg orally twice daily for 10 days (adults) or 20 mg/kg per dose twice daily (maximum 500 mg/dose) for 10 days (children) 1, 2
• Cefadroxil: 1 gram once daily for 10 days (adults) or 30 mg/kg once daily (maximum 1 gram) for 10 days (children) 1, 2
• Cross-reactivity risk is only 0.1% in patients with non-severe, delayed penicillin reactions 1

Immediate/Anaphylactic Penicillin Allergy

• Patients with anaphylaxis, angioedema, or immediate urticaria to penicillin must avoid ALL beta-lactam antibiotics, including cephalosporins, due to up to 10% cross-reactivity risk 1, 2
• Clindamycin: 300 mg orally three times daily for 10 days (adults) or 7 mg/kg per dose three times daily (maximum 300 mg/dose) for 10 days (children) 1, 2
• Clindamycin has strong, moderate-quality evidence with only ~1% resistance rate in the US and demonstrates high efficacy even in chronic carriers 1
• Azithromycin: 500 mg once daily for 5 days (adults) or 12 mg/kg once daily (maximum 500 mg) for 5 days (children) 1, 2, 7
• Azithromycin requires only 5 days due to prolonged tissue half-life but has 5-8% macrolide resistance in the US 1, 7
• Clarithromycin: 250 mg twice daily for 10 days (adults) or 7.5 mg/kg per dose twice daily (maximum 250 mg/dose) for 10 days (children) 1, 2

Critical Treatment Duration Requirements

• A full 10-day course is essential for ALL antibiotics except azithromycin to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent acute rheumatic fever 1, 2, 3
• Shortening the course by even a few days results in appreciable increases in treatment failure rates and rheumatic fever risk 1, 2
• Azithromycin is the sole exception, requiring only 5 days due to its unique pharmacokinetics 1, 2, 7
• Treatment should continue for a minimum of 48-72 hours beyond symptom resolution 3

Important Resistance Considerations

• Penicillin resistance does not exist in Group A Streptococcus—there has never been documented resistance anywhere in the world 1
• Macrolide resistance (azithromycin, clarithromycin) is approximately 5-8% in the United States but varies geographically 1, 2, 4
• Clindamycin resistance remains very low at approximately 1% among Group A Streptococcus 1, 2
• Data establishing efficacy of azithromycin in subsequent prevention of rheumatic fever are not available 7

Adjunctive Symptomatic Treatment

• Acetaminophen or NSAIDs (such as ibuprofen) for moderate to severe symptoms or high fever 1, 2
• Aspirin must be avoided in children due to Reye syndrome risk 1, 2
• Corticosteroids are NOT recommended as adjunctive therapy 1, 5

Post-Treatment Follow-Up

• Routine follow-up throat cultures or RADT are NOT recommended for asymptomatic patients who have completed therapy 1, 2
• Testing should only be considered in special circumstances, such as patients with a history of rheumatic fever 1
• Patients become non-contagious after 24 hours of appropriate antibiotic therapy 2

Common Pitfalls to Avoid

• Do NOT use trimethoprim-sulfamethoxazole (Bactrim)—it is absolutely contraindicated because sulfonamides do not eradicate Group A Streptococcus 1
• Do NOT prescribe cephalosporins to patients with immediate/anaphylactic penicillin reactions 1, 2
• Do NOT prescribe broad-spectrum cephalosporins (cefdinir, cefixime, cefpodoxime) when narrow-spectrum first-generation agents are appropriate—they are more expensive and select for resistant flora 1
• Do NOT shorten antibiotic courses below 10 days (except azithromycin's 5-day regimen)—this dramatically increases treatment failure and rheumatic fever risk 1, 2
• Do NOT use azithromycin as first-line therapy—it should only be used when penicillin and preferred alternatives cannot be used 1

Special Considerations for Recurrent Infections

• Consider whether the patient is experiencing true recurrent infections versus chronic carrier status with viral infections 1, 5
• Clindamycin is particularly effective for chronic carriers or treatment failures, with substantially higher eradication rates than penicillin or amoxicillin 1
• Chronic carriers generally do not require treatment unless special circumstances exist (community outbreak, family history of rheumatic fever) 1
• Tonsillectomy may be considered only for patients meeting specific frequency criteria: ≥7 episodes in 1 year, ≥5 episodes per year for 2 years, or ≥3 episodes per year for 3 years 5, 4