What is the first-line treatment for a patient with streptococcal (Group A beta-hemolytic streptococcus) pharyngitis (strep throat)?

First-Line Treatment for Streptococcal Pharyngitis

Penicillin or amoxicillin for 10 days is the first-line treatment for strep throat, with penicillin V 500 mg twice daily or amoxicillin 50 mg/kg once daily (maximum 1,000 mg) for adults and children respectively. 1

Why Penicillin/Amoxicillin Remains First-Line

• Penicillin is the drug of choice because of its proven efficacy, safety, narrow spectrum of activity, low cost, and the fact that no penicillin resistance has been documented in Group A Streptococcus anywhere in the world 1, 2

• Amoxicillin is equally effective to penicillin V and is often preferred in young children due to better palatability of the suspension 1, 3

• Both agents have strong, high-quality evidence supporting their use for achieving maximal pharyngeal bacterial eradication and preventing acute rheumatic fever 1, 3

Specific Dosing Regimens

For patients WITHOUT penicillin allergy:

• Penicillin V (oral): Children receive 250 mg two or three times daily; adolescents and adults receive 250 mg four times daily or 500 mg twice daily for 10 days 1

• Amoxicillin (oral): 50 mg/kg once daily (maximum 1,000 mg) or alternatively 25 mg/kg twice daily (maximum 500 mg) for 10 days 1, 3

• Penicillin G benzathine (intramuscular): Single dose of 600,000 units for patients <60 lb (27 kg) or 1,200,000 units for patients ≥60 lb, useful when compliance with oral therapy is questionable 1

For Patients WITH Penicillin Allergy

The treatment algorithm depends on the TYPE of penicillin allergy:

Non-Immediate (Non-Anaphylactic) Penicillin Allergy:

• First-generation cephalosporins are preferred alternatives with strong, high-quality evidence 1, 3, 2

• Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days 1, 2

• Cefadroxil: 30 mg/kg once daily (maximum 1 gram) for 10 days 1, 2

• Cross-reactivity risk with penicillin is only 0.1% in patients with non-severe, delayed penicillin reactions 2

Immediate/Anaphylactic Penicillin Allergy:

• All beta-lactam antibiotics must be avoided due to up to 10% cross-reactivity risk 1, 3, 2

• Clindamycin is the preferred choice: 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days, with only ~1% resistance rate in the United States 1, 3, 2

• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days is acceptable but has 5-8% macrolide resistance in the United States 1, 3, 2

• Clarithromycin: 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days 1, 2

Critical Treatment Duration Requirements

• A full 10-day course is mandatory for all antibiotics except azithromycin to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent acute rheumatic fever 1, 3, 4, 2

• Azithromycin requires only 5 days due to its prolonged tissue half-life and unique pharmacokinetics 1, 4, 2

• Shortening the antibiotic course by even a few days dramatically increases treatment failure rates and rheumatic fever risk 3, 2

Adjunctive Therapy

• Acetaminophen or NSAIDs (such as ibuprofen) should be considered for moderate to severe symptoms or high fever, with NSAIDs being more effective than acetaminophen for pain and fever control 1, 3, 5

• Aspirin must be avoided in children due to risk of Reye syndrome 1, 3, 2

• Corticosteroids are not recommended as adjunctive therapy 1, 3, 2

Common Pitfalls to Avoid

• Do not use azithromycin or other macrolides as first-line therapy when penicillin can be used—reserve them only for documented penicillin allergy 2

• Do not prescribe cephalosporins to patients with immediate/anaphylactic penicillin reactions due to the 10% cross-reactivity risk 1, 3, 2

• Do not use trimethoprim-sulfamethoxazole, tetracyclines, or sulfonamides for strep throat as they fail to eradicate streptococci effectively 3, 2

• Do not perform routine follow-up throat cultures in asymptomatic patients who have completed therapy 1, 4, 2

• Do not test or treat asymptomatic household contacts unless special circumstances exist 1

When NOT to Test or Treat

• Diagnostic testing is not recommended if clinical features strongly suggest viral etiology (cough, rhinorrhea, hoarseness, oral ulcers, conjunctivitis, coryza, diarrhea) 1

• Testing is generally not recommended in children younger than three years unless risk factors exist (such as an older sibling with the illness) 1

• Chronic carriers generally do not require antimicrobial therapy as they are unlikely to spread infection and are at little risk for complications 2