What are the empirical antibiotics for suspected bacterial pharyngitis?

From the Guidelines

Empirical antibiotics are not recommended for suspected bacterial pharyngitis without confirmation through rapid antigen detection testing or throat culture. If testing confirms Group A Streptococcus (GAS), the first-line treatment is penicillin V potassium 500 mg orally twice daily for 10 days, or amoxicillin 500 mg orally twice daily for 10 days, as recommended by the Infectious Diseases Society of America 1. For penicillin-allergic patients, alternatives include cephalexin 500 mg orally twice daily for 10 days (if no anaphylaxis history), or azithromycin 500 mg orally once daily for 5 days 1. Intramuscular benzathine penicillin G 1.2 million units as a single dose is an option for patients with compliance concerns.

Key considerations in selecting an antimicrobial for treatment of GAS pharyngitis include efficacy, safety, antimicrobial spectrum, dosing schedule, compliance with therapy, and cost 1. Penicillin remains the treatment of choice due to its proven efficacy and safety, narrow spectrum, and low cost 1. Amoxicillin is often used in place of penicillin V as oral therapy for young children, with equal efficacy 1.

Treatment aims to prevent complications like rheumatic fever and reduce symptom duration and transmission. Most pharyngitis cases are viral and self-limiting, so antibiotic stewardship is important to prevent unnecessary treatment and antimicrobial resistance 1. Symptomatic relief with analgesics, adequate hydration, and rest should be recommended for all patients regardless of etiology.

Some key points to consider:

• Penicillin-resistant GAS has never been documented 1
• Clindamycin resistance among GAS isolates in the United States is approximately 1% 1
• Macrolide resistance rates among pharyngeal isolates in most areas of the United States have been around 5%–8% 1
• Tetracyclines, sulfonamides, and trimethoprim-sulfamethoxazole should not be used to treat GAS pharyngitis due to high prevalence of resistant strains or lack of efficacy 1

From the FDA Drug Label

In three double-blind controlled studies, conducted in the United States, azithromycin (12 mg/kg once a day for 5 days) was compared to penicillin V (250 mg three times a day for 10 days) in the treatment of pharyngitis due to documented Group A β-hemolytic streptococci (GABHS or S. pyogenes) Azithromycin was clinically and microbiologically statistically superior to penicillin at Day 14 and Day 30 with the following clinical success (i.e., cure and improvement) and bacteriologic efficacy rates (for the combined evaluable patient with documented GABHS): Three U. S. Streptococcal Pharyngitis Studies Azithromycin vs. Penicillin V EFFICACY RESULTS Day 14 Day 30 Bacteriologic Eradication: Azithromycin 323/340 (95%) 255/330 (77%) Penicillin V 242/332 (73%) 206/325 (63%) Clinical Success (Cure plus improvement): Azithromycin 336/343 (98%) 310/330 (94%) Penicillin V 284/338 (84%) 241/325 (74%)

Empirical antibiotics for suspected bacterial pharyngitis can be treated with azithromycin. The clinical success rate for azithromycin was 98% at Day 14 and 94% at Day 30, which was statistically superior to penicillin V. The bacteriologic eradication rate for azithromycin was 95% at Day 14 and 77% at Day 30. 2

From the Research

Empirical Antibiotics for Suspected Bacterial Pharyngitis

• The use of empirical antibiotics for suspected bacterial pharyngitis is a topic of debate, with various studies providing guidance on the appropriate use of antibiotics 3, 4, 5, 6, 7.
• According to the principles of appropriate antibiotic use for acute pharyngitis in adults, antibiotics should only be prescribed to patients who are most likely to have Group A beta-hemolytic streptococcus (GABHS) infection 3.
• The Centor criteria, which include history of fever, tonsillar exudates, no cough, and tender anterior cervical lymphadenopathy, can be used to clinically screen patients with pharyngitis for the presence of GABHS infection 3, 4, 5.
• Rapid antigen detection tests and throat cultures can be used to diagnose GABHS infection, with penicillin and amoxicillin being the preferred antibiotics for treatment 4, 5, 7.
• However, there is significant resistance to azithromycin and clarithromycin in some parts of the United States, and first-generation cephalosporins are recommended for patients with nonanaphylactic allergies to penicillin 5.
• The use of antibiotics should be minimized to prevent unnecessary use and reduce the risk of antibiotic resistance, with a thorough history and physical examination being key to diagnosing pharyngitis and providing targeted treatment 6, 7.

Diagnosis and Treatment

• The diagnosis of streptococcal pharyngitis can be made using clinical decision rules, rapid antigen testing, and throat culture 4, 5, 7.
• The treatment of streptococcal pharyngitis typically involves the use of antibiotics, such as penicillin or amoxicillin, for a period of 10 days 4, 5.
• However, the use of antibiotics should be guided by clinical judgment and should only be prescribed to patients who are most likely to have GABHS infection 3, 4, 5.
• Steroids are not recommended for symptomatic treatment, and patients with worsening symptoms after appropriate antibiotic initiation or with symptoms lasting 5 days after the start of treatment should be reevaluated 5.

Clinical Guidelines and Controversies

• Clinical guidelines for the diagnosis and treatment of streptococcal pharyngitis vary significantly between professional associations, and there is substantial evidence that most physicians do not follow any published guidelines 7.
• The use of antibiotics for streptococcal pharyngitis is a controversial topic, with some arguing that antibiotics should only be prescribed to patients with severe symptoms or those who are at high risk of complications 7.
• However, others argue that antibiotics should be prescribed to all patients with GABHS infection, regardless of symptom severity, to prevent complications and reduce the risk of contagion 4, 5.