Which antibiotic would be suitable for a patient with a penicillin allergy diagnosed with strep throat?

Azithromycin is an appropriate choice for a patient with a penicillin allergy diagnosed with strep throat. This antibiotic belongs to the macrolide class and is effective against Streptococcus pyogenes, the bacteria commonly responsible for strep throat. Patients with a penicillin allergy need alternative options, as penicillin is typically the first-line treatment for this infection. Azithromycin is generally well-tolerated and provides a good therapeutic option, especially in individuals who cannot take penicillin.

The other antibiotics listed are not suitable due to various reasons closely related to the patient's allergy and the infection type. Ciprofloxacin, while effective against certain bacterial infections, is a fluoroquinolone that is not the preferred choice for strep throat. Nafcillin is a penicillin derivative, making it contraindicated for anyone with a penicillin allergy. Amoxicillin, similar to nafcillin, is part of the penicillin family and would pose a risk of allergic reaction for those with a penicillin allergy. Thus, azithromycin stands out as the safest and most appropriate option in this scenario.