What is the recommended antibiotic treatment for strep throat in adults?

Antibiotic Treatment for Strep Throat in Adults

Penicillin V (500 mg orally 2-3 times daily for 10 days) or amoxicillin (50 mg/kg once daily, maximum 1000 mg, for 10 days) is the first-line treatment for strep throat in adults. 1, 2

First-Line Treatment Options

For Non-Penicillin Allergic Patients:

• Penicillin V: 500 mg orally 2-3 times daily for 10 days 1
• Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) for 10 days 1, 2
  • Amoxicillin is equally effective as penicillin and may be more palatable 3
  • Once-daily dosing of amoxicillin has been shown to be as effective as multiple daily doses, potentially improving compliance 4, 5

For Penicillin-Allergic Patients:

• Non-anaphylactic allergy:

  • Cephalexin: 20 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1, 2
  • Cefadroxil: 30 mg/kg once daily (maximum 1 g) for 10 days 1

• Immediate hypersensitivity/anaphylactic allergy:

  • Clindamycin: 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days 1, 2
  • Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 2
  • Clarithromycin: 7.5 mg/kg twice daily (maximum 250 mg per dose) for 10 days 1, 2

Important Clinical Considerations

Diagnosis

• Use Centor criteria to assess likelihood of strep throat: fever, tonsillar exudates, tender anterior cervical adenopathy, and absence of cough 2
• Patients with 0-2 Centor criteria are unlikely to have GAS infection and don't require testing 2
• Patients with 3-4 criteria should be tested with rapid antigen detection test (RADT) and/or throat culture 2
• Presence of rhinorrhea, cough, hoarseness, or oral ulcers suggests viral etiology rather than strep throat 2

Treatment Duration

• A full 10-day course of antibiotics is critical to prevent rheumatic fever, even if symptoms resolve earlier 1, 2
• The only exception is azithromycin, which is given for 5 days 1, 2

Potential Pitfalls

• Macrolide resistance: Resistance of Group A streptococcus to azithromycin and clarithromycin is well-known and varies geographically 1
• Compliance issues: Once-daily amoxicillin may improve compliance compared to multiple daily doses of penicillin 4, 5
• Empiric treatment: Avoid prescribing antibiotics without testing, as this contributes to antibiotic resistance 2

Symptom Management

• NSAIDs or acetaminophen for pain and fever relief 2
• Warm salt water gargles and throat lozenges may help manage symptoms 2

Special Situations

Chronic Carriers

For patients who are chronic carriers of Group A streptococcus, alternative regimens include:

• Clindamycin: 20-30 mg/kg/day in three doses (maximum 300 mg per dose) for 10 days 1
• Penicillin V plus rifampin: Penicillin V for 10 days with rifampin added for the last 4 days 1
• Amoxicillin/clavulanate: 40 mg amoxicillin/kg/day in three doses (maximum 2000 mg amoxicillin/day) for 10 days 1

Follow-up

• Patients are considered non-contagious after 24 hours of appropriate antibiotic therapy 2
• Routine follow-up cultures are not necessary for asymptomatic patients who have completed a full course of therapy 2

Remember that completing the full course of antibiotics is essential, even if symptoms improve, to prevent complications such as rheumatic fever and treatment failure.