Antibiotics that treat strep throat primarily target the bacteria Group A Streptococcus. The first-line antibiotics recommended are:

• Penicillin (Penicillin V orally or Benzathine penicillin G intramuscularly)
• Amoxicillin (oral)

These are preferred because they are effective, safe, inexpensive, and there has been no documented resistance of Group A strep to penicillin

. For patients allergic to penicillin, alternative antibiotics include:

• Cephalexin or Cefadroxil (narrow-spectrum cephalosporins)
• Clindamycin
• Azithromycin
• Clarithromycin

Note that cephalexin and cefadroxil should be avoided in patients with immediate hypersensitivity to penicillin. Resistance has been reported to azithromycin and clarithromycin in some cases

. Treatment courses typically last around 10 days to ensure complete eradication of the bacteria and prevent complications such as rheumatic fever

. In summary, the antibiotics used to treat strep throat are:

• First choice: Penicillin or Amoxicillin
• Alternatives for penicillin-allergic patients: Cephalexin, Cefadroxil, Clindamycin, Azithromycin, Clarithromycin

These antibiotics reduce symptom duration, transmission risk, and complications associated with strep throat