In streptococcal pharyngitis, which antibiotic is commonly used when penicillin allergy is present?

In streptococcal pharyngitis, which antibiotic is commonly used when penicillin allergy is present?

• A. Fluoroquinolones
• B. Aminoglycosides
• C. Macrolides (erythromycin)
• D. Tetracyclines

Answer: (C)

When penicillin cannot be used for streptococcal pharyngitis, you choose an antibiotic with proven activity against Streptococcus pyogenes and a safety profile suitable for penicillin-allergic patients. A macrolide, such as erythromycin, is a classic and commonly used alternative. Macrolides inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit, effectively stopping growth in streptococci, which makes them reliable for treating GAS pharyngitis in those who cannot take penicillin. Other options listed are less appropriate for this infection: fluoroquinolones aren’t preferred for GAS pharyngitis due to resistance and safety considerations; aminoglycosides have poor activity against streptococci; tetracyclines are not ideal in children and have compatibility concerns. So the macrolide, represented here by erythromycin, is the appropriate substitute.

When penicillin cannot be used for streptococcal pharyngitis, you choose an antibiotic with proven activity against Streptococcus pyogenes and a safety profile suitable for penicillin-allergic patients. A macrolide, such as erythromycin, is a classic and commonly used alternative. Macrolides inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit, effectively stopping growth in streptococci, which makes them reliable for treating GAS pharyngitis in those who cannot take penicillin. Other options listed are less appropriate for this infection: fluoroquinolones aren’t preferred for GAS pharyngitis due to resistance and safety considerations; aminoglycosides have poor activity against streptococci; tetracyclines are not ideal in children and have compatibility concerns. So the macrolide, represented here by erythromycin, is the appropriate substitute.