What is the recommended treatment for strep throat in an 11-year-old patient weighing 120 pounds?

Treatment of Strep Throat in an 11-Year-Old Weighing 120 Pounds

Amoxicillin 50 mg/kg once daily (maximum 1000 mg) for 10 days is the recommended first-line treatment for strep throat in this 11-year-old patient. 1

First-Line Treatment Options

For this 11-year-old weighing 120 pounds (approximately 54.5 kg):

• Amoxicillin:

  • Dosage: 50 mg/kg once daily (maximum 1000 mg) for 10 days 1
  • This would be approximately 1000 mg (maximum dose) once daily
  • Alternative dosing: 25 mg/kg twice daily (maximum 500 mg per dose) 1

• Penicillin V:

  • Dosage: 250 mg 2-3 times daily for children 2, 1
  • For adolescents/adults: 500 mg 2-3 times daily 2, 1

Why Amoxicillin is Preferred

Amoxicillin is often preferred over penicillin V because:

• Once-daily dosing improves compliance 1, 3
• More palatable than penicillin V suspension, especially for children 2
• Relatively inexpensive 2
• Comparable efficacy to penicillin with better adherence rates 3

Important Treatment Considerations

• Duration: Complete the full 10-day course even if symptoms improve quickly to prevent rheumatic fever 2, 1, 4
• Timing: Take medication at the start of a meal to minimize gastrointestinal intolerance 4
• Contagiousness: Patient is considered non-contagious after 24 hours of appropriate antibiotic therapy 1

For Penicillin-Allergic Patients

If the patient has a penicillin allergy, alternative options include:

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

  • Note: Cephalosporin cross-reactivity occurs in about 10% of penicillin-allergic patients 1

• Clindamycin: 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days 1

• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1

  • Note: Higher bacteriological failure rates have been reported with azithromycin compared to penicillin 5

Adjunctive Therapy

• Consider analgesics or antipyretics (acetaminophen, NSAIDs) for moderate to severe symptoms or high fever 2, 1
• Important: Avoid aspirin in children due to risk of Reye's syndrome 2
• Warm salt water gargles and throat lozenges may help manage pain 1

Follow-Up Recommendations

• Post-treatment testing is not routinely recommended 2
• No routine follow-up is necessary for uncomplicated cases 1
• Advise return if:
  • Symptoms persist beyond 7 days
  • Difficulty swallowing or breathing develops
  • High fever persists despite antipyretics
  • Development of purulent tonsillar exudates or tender cervical lymphadenopathy 1

Common Pitfalls to Avoid

1. Incomplete treatment course: Failure to complete the full 10-day course may lead to treatment failure and risk of rheumatic fever 2, 1

2. Incorrect dosing: Underdosing may lead to treatment failure; for this 120-pound child, use the maximum dose of 1000 mg for once-daily amoxicillin 1, 4

3. Ignoring penicillin allergy: Always confirm allergy status before prescribing 2, 1

4. Treating without confirmation: Ensure diagnosis is confirmed by rapid antigen detection test and/or culture before starting antibiotics 2