What is the recommended oral antibiotic regimen for a patient with beta haemolytic streptococcus (BHS) tonsillitis?

Oral Antibiotic Treatment for Beta-Hemolytic Streptococcus Tonsillitis

Penicillin V remains the first-line oral antibiotic for beta-hemolytic streptococcus tonsillitis, dosed at 250 mg twice or three times daily for children, or 250 mg four times daily (or 500 mg twice daily) for adolescents and adults, for a full 10 days. 1

First-Line Treatment: Penicillin

• Penicillin V is the drug of choice for non-allergic patients due to its narrow spectrum, proven efficacy in preventing rheumatic fever, excellent safety profile, and low cost 1, 2
• The recommended duration is 10 days to maximize pharyngeal eradication and prevent acute rheumatic fever, even though symptoms typically resolve within 3-4 days 1, 2
• Amoxicillin is often substituted for penicillin V in young children due to better palatability of the suspension, with equivalent efficacy 1
• Intramuscular benzathine penicillin G (1.2 million units as a single dose for patients >60 lbs, or 600,000 units for patients <60 lbs) is preferred when compliance with a 10-day oral course is unlikely 1, 3

Alternative Regimens for Penicillin-Allergic Patients

Non-Anaphylactic Penicillin Allergy

• First-generation cephalosporins are the preferred alternatives, specifically cephalexin 20 mg/kg per dose twice daily (maximum 500 mg per dose) or cefadroxil 30 mg/kg once daily for 10 days 3, 2
• Cross-reactivity risk with first-generation cephalosporins is only 0.1% in patients with non-immediate, delayed penicillin reactions 2
• These agents have strong, high-quality evidence supporting their efficacy and are superior to broader-spectrum alternatives in terms of cost and resistance profile 2

Immediate/Anaphylactic Penicillin Allergy

• Patients with immediate hypersensitivity reactions must avoid all beta-lactam antibiotics, including cephalosporins, due to up to 10% cross-reactivity risk 2
• Clindamycin is the preferred choice at 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days, with only ~1% resistance among Group A Streptococcus in the United States 3, 2
• Azithromycin is an acceptable alternative at 12 mg/kg once daily (maximum 500 mg) for 5 days, though macrolide resistance is 5-8% in the United States and varies geographically 3, 2, 4
• Clarithromycin 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days is another option, but shares the same resistance concerns as azithromycin 2
• Erythromycin 20-40 mg/kg/day divided 2-3 times daily (maximum 1 gram per day) for 10 days is less preferred due to high rates of gastrointestinal side effects 1, 5

Critical Treatment Duration Requirements

• All antibiotics except azithromycin require a full 10-day course to achieve maximal pharyngeal eradication and prevent acute rheumatic fever 1, 2
• Azithromycin is the only exception, requiring just 5 days due to its prolonged tissue half-life 2, 4
• Shortening courses by even a few days results in appreciable increases in treatment failure rates and rheumatic fever risk 1, 2
• Therapy can be safely postponed up to 9 days after symptom onset and still prevent acute rheumatic fever 2

Evidence on Shorter Courses with Other Antibiotics

• While some studies suggest 5-day courses of certain cephalosporins (cefuroxime, cefpodoxime) may achieve comparable bacteriologic cure rates, definitive comprehensive studies are not available to endorse these shorter courses 1
• A Cochrane review found short-duration newer antibiotics (2-6 days) showed slightly better clinical outcomes but more gastrointestinal side effects compared to 10 days of penicillin, with small clinical differences that are difficult to interpret since different antibiotic types were compared 1
• One study found penicillin treatment for 7 days was superior to 3 days in resolving symptoms 1

Important Resistance and Efficacy Considerations

• No penicillin resistance has been documented in Group A Streptococcus anywhere in the world 2
• Macrolide resistance varies geographically and temporally, ranging from 5-8% in the United States but can be much higher in some regions 2
• Clindamycin resistance remains very low at approximately 1% in the United States, making it more reliable than macrolides when beta-lactams cannot be used 2
• Clindamycin demonstrates high efficacy even in chronic streptococcal carriers who have failed penicillin treatment 2

Common Pitfalls to Avoid

• Do not use cephalosporins in patients with immediate/anaphylactic penicillin reactions due to the 10% cross-reactivity risk 2
• Do not prescribe broad-spectrum cephalosporins (cefaclor, cefuroxime, cefixime, cefdinir, cefpodoxime) when narrow-spectrum first-generation agents are appropriate, as they are more expensive and select for resistant flora 2
• Do not use trimethoprim-sulfamethoxazole (Bactrim) for strep throat due to high resistance rates and lack of efficacy against Group A Streptococcus 2
• Do not shorten treatment courses below 10 days (except azithromycin's 5-day regimen) despite clinical improvement, as this increases treatment failure and rheumatic fever risk 2
• Do not routinely perform post-treatment throat cultures for asymptomatic patients who have completed therapy; testing should only be considered in special circumstances such as patients with a history of rheumatic fever 3, 2

Adjunctive Therapy

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