What is the recommended treatment for a non-pregnant adult with strep throat and no significant medical history?

Treatment for Strep Throat in Non-Pregnant Adults

For a non-pregnant adult with confirmed streptococcal pharyngitis and no penicillin allergy, prescribe penicillin V 500 mg orally twice daily for 10 days or amoxicillin 500 mg orally twice daily for 10 days. 1

Confirm the Diagnosis First

Before prescribing antibiotics, laboratory confirmation is essential. 2, 1

• Use the modified Centor criteria to determine who needs testing: fever by history, tonsillar exudates, tender anterior cervical adenopathy, and absence of cough. 1
• Patients with fewer than 3 Centor criteria do not need testing and should not receive antibiotics. 2, 1
• For patients with 3-4 Centor criteria, perform a rapid antigen detection test (RADT). 3
• In adults, a negative RADT does not require confirmation with throat culture (unlike in children). 1
• Only treat patients with confirmed streptococcal pharyngitis - over 60% of adults with sore throat receive unnecessary antibiotics. 2

First-Line Antibiotic Therapy

Penicillin remains the drug of choice due to proven efficacy, narrow spectrum, safety, and low cost, with no documented penicillin resistance in Group A Streptococcus anywhere in the world. 1, 3

Dosing Options for Non-Allergic Patients:

• Penicillin V 500 mg orally twice daily for 10 days (preferred oral option) 1
• Amoxicillin 500 mg orally twice daily for 10 days (alternative oral option) 1
• Benzathine penicillin G 1.2 million units intramuscularly as a single dose (for compliance concerns) 1

Why 10 Days?

The full 10-day course is essential to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent acute rheumatic fever. 4, 1 Shortening the course by even a few days results in appreciable increases in treatment failure rates. 4

Therapy can be safely initiated up to 9 days after symptom onset and still prevent acute rheumatic fever. 1

For Penicillin-Allergic Patients

The choice of alternative antibiotic depends critically on the type of allergic reaction. 4

Non-Immediate (Non-Anaphylactic) Penicillin Allergy:

First-generation cephalosporins are the preferred first-line alternatives with strong, high-quality evidence. 4

• Cephalexin 500 mg orally twice daily for 10 days 4
• Cross-reactivity risk is only 0.1% in patients with non-severe, delayed penicillin reactions. 4

Immediate/Anaphylactic Penicillin Allergy:

Patients with immediate hypersensitivity must avoid all beta-lactam antibiotics, including cephalosporins, due to up to 10% cross-reactivity risk. 4

Clindamycin is the preferred choice for immediate/anaphylactic reactions:

• Clindamycin 300 mg orally three times daily for 10 days 4
• Resistance rate is only ~1% in the United States, making it highly reliable. 4
• Particularly effective in chronic carriers and treatment failures. 4

Azithromycin is an acceptable alternative but less preferred:

• Azithromycin 500 mg orally once daily for 5 days 4, 5
• Macrolide resistance is 5-8% in the United States and varies geographically. 4, 5
• Azithromycin is the only antibiotic requiring just 5 days due to its prolonged tissue half-life. 4
• Data establishing efficacy in preventing rheumatic fever are not available for azithromycin. 5

Clarithromycin is also acceptable:

• Clarithromycin 250 mg orally twice daily for 10 days 4
• Same resistance concerns as azithromycin (5-8% macrolide resistance). 4

Clinical Benefits and Realistic Expectations

Antibiotics provide modest symptomatic benefit but are primarily prescribed to prevent complications. 2, 1

• Antibiotics shorten symptom duration by only 1-2 days. 2, 1, 6
• Number needed to treat is 6 at 3 days and 21 at 1 week to reduce symptoms. 2, 1
• The primary benefit is prevention of complications: acute rheumatic fever (reduced by more than two-thirds), peritonsillar abscess, and spread during outbreaks. 2, 1, 6
• Antibiotics reduce acute otitis media (RR 0.30) and quinsy/peritonsillar abscess (RR 0.15). 6

Symptomatic Management

Offer analgesics to all patients regardless of antibiotic use. 1, 3

• Acetaminophen or NSAIDs (such as ibuprofen) for moderate to severe symptoms or high fever. 4, 1
• Throat lozenges can help reduce pain. 2
• Avoid aspirin in children due to risk of Reye syndrome. 4, 3
• Do not use corticosteroids as adjunctive therapy. 4, 1

When NOT to Treat

Chronic Group A Streptococcus carriers should not be treated unless special circumstances exist. 4, 1

• Chronic carriers are unlikely to spread infection and are at little risk for complications. 2, 1
• They may have repeated positive tests during viral infections but do not require antimicrobial therapy. 4, 1
• Routine post-treatment testing is not recommended for asymptomatic patients who completed therapy. 1, 3

Critical Pitfalls to Avoid

• Do not prescribe antibiotics without laboratory confirmation - clinical symptoms alone are insufficient. 2, 3
• Do not use cephalosporins in patients with immediate/anaphylactic penicillin reactions due to 10% cross-reactivity risk. 4
• Do not shorten antibiotic courses below 10 days (except azithromycin's 5-day regimen) - this dramatically increases treatment failure and rheumatic fever risk. 4, 1
• Do not prescribe broad-spectrum antibiotics when narrow-spectrum agents are appropriate - this unnecessarily increases selection pressure for resistant organisms. 4, 3
• Do not use azithromycin as first-line therapy - it should only be used when penicillin and preferred alternatives cannot be used. 4
• Do not ignore local macrolide resistance patterns - resistance varies geographically and can be much higher than 5-8% in some areas. 4

When to Reevaluate

Patients should be reevaluated if:

• Symptoms worsen after appropriate antibiotic initiation 1
• Symptoms last 5 days after treatment starts 1
• Severe pharyngitis in adolescents/young adults - remain vigilant for Lemierre syndrome, a rare but life-threatening condition requiring urgent diagnosis. 2, 1

Evaluate for complications such as peritonsillar abscess, parapharyngeal abscess, epiglottitis, or Lemierre syndrome. 2, 1