Final answer:
For Group A Streptococcal pharyngitis in patients allergic to penicillin, the preferred treatments are clindamycin or clarithromycin due to their effectiveness against streptococcal infections and suitability for those with penicillin allergies.
Step-by-step explanation:
The treatment of choice for Group A Streptococcal (GAS) pharyngitis in patients allergic to penicillin is typically clindamycin or clarithromycin. Since patients with a penicillin allergy cannot receive the commonly prescribed ß-lactam antibiotics, such as amoxicillin or penicillin G, alternative antibiotics that are effective against streptococcal infections need to be considered. Clindamycin and clarithromycin are such alternatives, and they are often recommended when treating individuals with a known penicillin allergy.