If a patient has rheumatic fever and a suspected allergy to penicillin, what is the antibiotic of choice?

For a patient who has rheumatic fever and a suspected allergy to penicillin, erythromycin is the antibiotic of choice due to its effectiveness in treating streptococcal infections while being safe for patients with penicillin allergies. Rheumatic fever is often a complication of untreated group A streptococcal pharyngitis, and antibiotic therapy is essential to prevent further complications.

Erythromycin belongs to the macrolide class of antibiotics and provides an alternative for those who cannot tolerate penicillin. It works by inhibiting bacterial protein synthesis, making it effective against the types of bacteria usually associated with rheumatic fever.

While the other options may have their uses in different contexts, they are not suitable alternatives in this scenario. Chloromycetin (chloramphenicol) is generally reserved for severe infections due to its risk of serious side effects, particularly aplastic anemia. Sulphonamides may not be as effective against the specific strains of bacteria involved in rheumatic fever. Buffered penicillin, despite being a formulation of penicillin, would not be appropriate given the patient's allergy to penicillin. Thus, erythromycin stands out as the most suitable choice for this patient profile.