What is the preferred antibiotic for treating strep throat?

From the Guidelines

Penicillin V is the preferred antibiotic for treating strep throat, with a typical adult dosage of 250-500 mg orally twice daily for 10 days, as it has maintained susceptibility to Group A Streptococcus over decades and effectively prevents complications like rheumatic fever and post-streptococcal glomerulonephritis 1. The full 10-day course should be completed even if symptoms improve earlier to ensure complete eradication of the bacteria. For patients with penicillin allergy, alternatives include amoxicillin (500 mg twice daily for adults) or, in cases of true penicillin allergy, azithromycin (500 mg on day 1, then 250 mg daily for 4 more days) or clindamycin (300 mg three times daily for 10 days) 1. Some key points to consider when treating strep throat include:

• The importance of completing the full 10-day course of antibiotics to prevent complications and ensure complete eradication of the bacteria
• The need to consider alternative antibiotics for patients with penicillin allergy
• The effectiveness of penicillin in preventing complications like rheumatic fever and post-streptococcal glomerulonephritis
• The narrow spectrum of penicillin, which minimizes disruption to normal gut flora
• The relatively low cost of penicillin compared to other antibiotics It's also worth noting that other antibiotics, such as cephalexin and cefadroxil, may be effective alternatives for patients with penicillin allergy, but they should be used with caution and under the guidance of a healthcare professional 1. Overall, the choice of antibiotic for treating strep throat should be based on the individual patient's needs and medical history, as well as the most up-to-date evidence and guidelines 1.

From the FDA Drug Label

Pharyngitis/Tonsillitis 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 14Day 30 Bacteriologic Eradication: Azithromycin323/340 (95%)255/330 (77%) Penicillin V242/332 (73%)206/325 (63%) Clinical Success (Cure plus improvement): Azithromycin336/343 (98%)310/330 (94%) Penicillin V284/338 (84%)241/325 (74%)

The preferred antibiotic for treating strep throat is azithromycin, as it has been shown to be clinically and microbiologically statistically superior to penicillin V in three double-blind controlled studies.

• Bacteriologic Eradication rates were higher for azithromycin (95% at Day 14 and 77% at Day 30) compared to penicillin V (73% at Day 14 and 63% at Day 30).
• Clinical Success rates were also higher for azithromycin (98% at Day 14 and 94% at Day 30) compared to penicillin V (84% at Day 14 and 74% at Day 30) 2.

From the Research

Preferred Antibiotic for Treating Strep Throat

The preferred antibiotic for treating strep throat is not clearly established, as different studies have shown varying results. However, some antibiotics have been found to be more effective than others in certain situations.

• Penicillin: Penicillin is often considered the first-line treatment for strep throat, as it is effective against group A beta-hemolytic streptococci (GABHS) and has a low risk of adverse effects 3.
• Amoxicillin: Amoxicillin is also a commonly used antibiotic for treating strep throat, and it has been shown to be effective in reducing symptoms and preventing complications 4.
• Cephalosporins: Cephalosporins, such as azithromycin, have been found to be effective in treating strep throat, but they may have a higher risk of adverse effects compared to penicillin 5, 6.
• Carbacephem: Carbacephem has been shown to be effective in treating strep throat, particularly in adults and children, and may be a viable alternative to penicillin 5, 6.

Comparison of Antibiotics

Studies have compared the effectiveness of different antibiotics in treating strep throat, including:

• Cephalosporins vs. Penicillin: The evidence is uncertain regarding the difference in symptom resolution between cephalosporins and penicillin 5, 6.
• Macrolides vs. Penicillin: The evidence is also uncertain regarding the difference in symptom resolution between macrolides and penicillin 5, 6.
• Azithromycin vs. Amoxicillin: Azithromycin may be more effective than amoxicillin in treating strep throat in children, but the evidence is limited 5, 6.

Treatment Duration and Dosage

The optimal treatment duration and dosage for strep throat are also uncertain. However, some studies suggest that:

• Shorter treatment duration: A shorter treatment duration of 5 days may be effective in treating strep throat, particularly with penicillin V four times daily 7.
• Standard treatment duration: The standard treatment duration of 10 days is still widely recommended, particularly for patients with severe symptoms or signs of progression to locoregional suppuration 4, 3.