What are the recommended antibiotics for treating strep (streptococcal) infections?

From the Guidelines

Penicillin is the first-line antibiotic treatment for streptococcal infections, particularly Group A Streptococcus (GAS) which causes strep throat, as it has a narrow spectrum of activity and no resistance has been reported, as stated in the 2012 update by the Infectious Diseases Society of America 1. For adults with strep throat, oral penicillin V (250-500 mg twice daily for 10 days) or amoxicillin (500 mg twice daily or 1000 mg once daily for 10 days) is recommended. For children, weight-based dosing is used:

• penicillin V (250 mg twice daily for children <27 kg; 500 mg twice daily for those ≥27 kg)
• or amoxicillin (50 mg/kg once daily, maximum 1000 mg) 1. For penicillin-allergic patients,
• first-generation cephalosporins like cephalexin are preferred if the allergy is non-severe
• while macrolides such as azithromycin (500 mg on day 1, then 250 mg daily for 4 days) or clindamycin (300 mg three times daily for 10 days) are options for those with severe penicillin allergy 1. Completing the full course of antibiotics is crucial even if symptoms improve quickly, as this prevents complications like rheumatic fever and helps eliminate the bacteria completely. Some key points to consider when selecting an antimicrobial for treatment of group A streptococcal pharyngitis include efficacy, safety, antimicrobial spectrum, dosing schedule, associated compliance with therapy, and cost, as outlined in the 2002 practice guidelines by the Infectious Diseases Society of America 1. Additionally, the American Heart Association recommends prevention of rheumatic fever through adequate therapy for GAS pharyngitis, with intramuscular benzathine penicillin G and oral penicillin V as the recommended antimicrobial drugs, except in individuals with histories of penicillin allergy 1. It's also important to note that no regimen eradicates GAS from the pharynx in 100% of treated patients, even though 100% of GAS demonstrate in vitro susceptibility to all-lactam agents (penicillins and cephalosporins) 1. Overall, the choice of antibiotic should be based on the patient's specific needs and medical history, and the treatment should always be guided by the most recent and highest quality evidence available, such as the 2012 update by the Infectious Diseases Society of America 1.

From the FDA Drug Label

Amoxicillin is indicated in the treatment of infections due to susceptible (ONLY β-lactamase–negative) isolates of Streptococcus species. (α- and β-hemolytic isolates only) It is recommended that there be at least 10 days’ treatment for any infection caused by Streptococcus pyogenes to prevent the occurrence of acute rheumatic fever. Skin and skin structure infections of mild to moderate severity caused by Streptococcus pyogenes or Staphylococcus aureus (resistant staphylococci may emerge during treatment).

The recommended antibiotics for treating strep (streptococcal) infections are:

• Amoxicillin 2: for the treatment of infections due to susceptible isolates of Streptococcus species
• Erythromycin 3: for the treatment of skin and skin structure infections of mild to moderate severity caused by Streptococcus pyogenes Key points:
• At least 10 days of treatment is recommended for any infection caused by Streptococcus pyogenes to prevent acute rheumatic fever.
• The choice of antibiotic should be based on the severity of the infection and the susceptibility of the causative organism.

From the Research

Recommended Antibiotics for Strep Infections

The following antibiotics are recommended for treating strep (streptococcal) infections:

• Penicillin: Most authorities continue to recommend penicillin as the treatment of choice for group A streptococcal pharyngitis 4
• Cephalosporins: Oral cephalosporins, such as cefpodoxime proxetil, are significantly superior to penicillin V in eradicating group A streptococci from the pharynx 4
• Erythromycin: Erythromycin is a safe and effective antibiotic for the treatment of streptococcal pharyngitis, especially in patients allergic to penicillin 5
• Macrolides: Newer macrolides, such as clarithromycin and azithromycin, offer lower rates of gastrointestinal complaints and more convenient dosing, and are rational alternatives to erythromycin for streptococcal pharyngitis/tonsillitis in penicillin-allergic patients 6

Dosage and Duration of Treatment

The recommended dosage and duration of treatment for strep infections are:

• Penicillin V: 250 mg three times daily for 10 days 4, or 500 mg twice daily for 10 days 7
• Cefpodoxime proxetil: twice daily for 10 days 4, or 5-day therapy with cefpodoxime (or other selected oral cephalosporins) 4
• Erythromycin: 20 to 30 mg/kg/day for erythromycin estolate, and 40 mg/kg/day for erythromycin ethylsuccinate, for 10 days 5
• Macrolides: clarithromycin twice daily, and azithromycin once daily, for 5-10 days 6