What is the treatment for strep throat?

Treatment for Strep Throat

Penicillin V remains the first-line treatment of choice for strep throat, dosed at 250 mg three to four times daily (or 500 mg twice daily) for adults and older children, or amoxicillin 50 mg/kg once daily (maximum 1000 mg) for 10 days in younger children, due to its proven efficacy, safety, narrow spectrum, and low cost. 1, 2

First-Line Treatment Options

Oral Penicillin (Preferred)

• Penicillin V is the drug of choice because no clinical isolate of group A streptococcus has ever been documented to be resistant to penicillin anywhere in the world 1
• Adults and older children: 250 mg three to four times daily OR 500 mg twice daily for 10 days 1, 2
• Younger children: Amoxicillin 50 mg/kg once daily (maximum 1000 mg) for 10 days is preferred over penicillin V due to better taste acceptance and availability as suspension 2
• Critical: A full 10-day course is required to achieve maximal pharyngeal eradication of group A streptococci and prevent acute rheumatic fever 1, 3, 4

Intramuscular Benzathine Penicillin G

• Single dose of 1.2 million units intramuscularly is an effective alternative when compliance with 10-day oral therapy is unlikely 1, 2
• This has proven effectiveness in both primary and secondary prevention of rheumatic fever 1

Treatment for Penicillin-Allergic Patients

Non-Immediate (Non-Anaphylactic) Penicillin Allergy

• First-generation cephalosporins are the preferred first-line alternatives 3, 2
• Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg/dose) for 10 days 3
• Cefadroxil: 30 mg/kg once daily (maximum 1 gram) for 10 days 3
• Cross-reactivity risk with penicillin is less than 3%, making these safe in most penicillin-allergic patients 5

Immediate/Anaphylactic Penicillin Allergy

• Avoid all beta-lactams including cephalosporins due to up to 10% cross-reactivity risk 3
• Clindamycin is the preferred alternative: 7 mg/kg per dose three times daily (maximum 300 mg/dose) for 10 days 3, 2
• Clindamycin demonstrates high efficacy in eradicating streptococci, even in chronic carriers, with only 1% resistance in the United States 3
• Alternative macrolides include:
  • Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 3, 2
  • Clarithromycin: 7.5 mg/kg per dose twice daily (maximum 250 mg/dose) for 10 days 3
  • Erythromycin: 20-40 mg/kg/day divided 2-3 times daily for 10 days 1, 3

Important Considerations About Macrolides

• Macrolide resistance among group A streptococcus is approximately 5-8% in the United States, though this varies geographically and temporally 3
• Azithromycin is the only antibiotic that requires only 5 days of treatment due to its prolonged tissue half-life 3, 2
• However, research shows that 10 days of clarithromycin may be more effective than 5 days of azithromycin in bacterial eradication (91% vs 82%, P=0.012) 6
• Azithromycin should not be relied upon to treat syphilis, and susceptibility testing should be performed when treating with macrolides 7

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, 3, 4
• Therapy must be sufficient to eliminate the organism; otherwise sequelae of streptococcal disease may occur 4
• Patients become non-contagious after 24 hours of appropriate antibiotic therapy 5

Common Pitfalls to Avoid

• Do not use amoxicillin or ampicillin in patients with concurrent infectious mononucleosis due to risk of rash; use first-generation cephalosporin or macrolide instead 5
• Do not prescribe shorter courses than recommended (except for azithromycin) as this leads to treatment failure and complications 3
• Do not assume all penicillin-allergic patients cannot receive cephalosporins—only those with immediate/anaphylactic reactions should avoid them 3
• Do not use sulfonamides or tetracyclines due to high resistance rates among group A streptococci 1
• Do not use trimethoprim-sulfamethoxazole as resistance rates are approximately 50% 3
• Do not perform routine follow-up throat cultures in asymptomatic patients who have completed therapy 3, 5

Special Clinical Scenarios

Recurrent Streptococcal Pharyngitis

• Clindamycin may be particularly effective due to its ability to eradicate the organism in chronic carriers 3
• Chronic carriers generally do not require antimicrobial therapy as they are unlikely to spread infection or develop complications 3

Adjunctive Therapy

• Acetaminophen or NSAIDs can be used for moderate to severe symptoms or high fever 3
• Avoid aspirin in children due to risk of Reye syndrome 3
• Corticosteroids are not recommended as adjunctive therapy 3

Evidence on Symptom Reduction

• Recent high-quality evidence suggests that antibiotics have limited impact on symptom duration, with placebo being non-inferior to amoxicillin in reducing fever duration (mean difference 2.8 hours) 8
• However, the primary justification for antibiotic treatment remains prevention of suppurative complications and rheumatic fever, not just symptom relief 8
• Short-duration antibiotics (3-6 days) show comparable clinical efficacy to 10-day penicillin but have higher rates of late bacteriological recurrence 9