What is the first line treatment for strep throat?

First-Line Treatment for Strep Throat

Penicillin V is the first-line treatment for strep throat (Group A Streptococcal pharyngitis), recommended at 250 mg four times daily or 500 mg twice daily for 10 days in adults. 1

Adult Treatment Options

• First-line therapy:

  • Penicillin V: 250 mg four times daily or 500 mg twice daily for 10 days 1
  • Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1

• For penicillin-allergic patients:

  • Azithromycin: 500 mg once daily for 5 days 1
  • Clindamycin: 300-450 mg orally three times daily for 10 days (if initial therapy fails) 1

Pediatric Treatment Options

• First-line therapy:
  • Penicillin V: 250 mg twice or three times daily for 10 days 1
  • Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1

Dosing Frequency Considerations

While penicillin has traditionally been dosed 3-4 times daily, twice-daily dosing of penicillin V has been shown to be equally effective 1, 2. This can significantly improve patient compliance with the full 10-day course. However, once-daily dosing of penicillin is associated with decreased efficacy and should not be used 2.

Amoxicillin may be given once daily with good efficacy, which could improve compliance 3. Studies have shown that once-daily amoxicillin (750 mg) is as effective as penicillin V given three times daily 3.

Treatment Duration

A full 10-day course of antibiotics is recommended for strep throat to:

• Prevent rheumatic fever
• Reduce the duration of symptoms
• Decrease the incidence of suppurative complications
• Limit spread of the disease 4

Common Pitfalls and Caveats

1. Compliance issues: The bacteriologic failure rate with penicillin therapy has increased over time, potentially due to poor compliance with the 10-day regimen 5. Consider twice-daily dosing to improve adherence.

2. Diagnostic confirmation: Clinical diagnosis alone is insufficient; bacteriologic confirmation is required before initiating treatment 1. Use the Centor Criteria to assess likelihood of GAS pharyngitis, and consider Rapid Antigen Detection Tests (RADTs) for patients with high likelihood (3-4 Centor criteria) 1.

3. Return to work/school: Patients should be isolated for a minimum of 24 hours after starting effective antibiotic therapy 1. Healthcare workers should be excluded from work until 24 hours of appropriate treatment and resolution of symptoms 1.

4. Treatment failures: If initial therapy fails, consider clindamycin as a second-line option 1. Treatment failures may be due to:

   • Poor compliance
   • Reexposure to infected individuals
   • Copathogenicity with other bacteria
   • Eradication of normal protective pharyngeal flora
   • Penicillin tolerance 5

5. Prevention measures: Hand hygiene, avoiding close contact with infected individuals, and not sharing utensils or drinks are important preventive measures 1.